Statement Of Changes In Equity [Abstract]
| Concept | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | |||||||||||||||||||||||||||||||||||
| Statement of changes in equity [line items] | |||||||||||||||||||||||||||||||||||
| Equity | — | 
                                                16, 328
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                121,080,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                22 , 537
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                1,833,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                6,806,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                68 ,09 5
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                9 , 147
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                16, 328
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                70, 20 5
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                22 , 537
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                6,806,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                2  ,1 9 4
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                124 ,17 8
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                10,49 6
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                135, 8 89
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                22, 530
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                6,805,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                3 ,017
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                78 , 5 6 1
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                1 6 , 328
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                14,682,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
| Changes in equity [abstract] | |||||||||||||||||||||||||||||||||||
| Comprehensive income [abstract] | |||||||||||||||||||||||||||||||||||
| Profit (loss) | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                1,0 40
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                1 ,04 0
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
                                                4 , 4 4 0
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                4 , 4 4 0
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Other comprehensive income | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                1,349,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                1,34 9
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
                                                4 , 1 8 6
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                4 , 1 8 6
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Comprehensive income | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                3 09
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                1 ,0 40
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                1,349,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
                                                8, 626
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                4 , 4 4 0
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                4 , 1 8 6
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Issue of equity | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
                                                8,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                7,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                1,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Dividends recognised as distributions to owners | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                3 , 23 5
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                3 , 23 5
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
                                                3 ,02 6
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                3 ,0 26
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Increase (decrease) through treasury share transactions, equity | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                36 1
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                361,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                823,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                8 2 3
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Increase (decrease) through share-based payment transactions, equity | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                446,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                446,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
                                                67,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                6 7
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — |