Statement Of Financial Position [Abstract]
| Concept | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 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 financial position [abstract] | |||||||||||||||||||||
| Assets [abstract] | |||||||||||||||||||||
| Non-current assets [abstract] | |||||||||||||||||||||
| Property, plant and equipment | — | 
                                                18 , 593
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                19,070,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Right-of-use assets | — | 
                                                20, 283
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                1 6, 450
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Investments accounted for using equity method | — | 
                                                353,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                159,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Trade and other non-current receivables | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Deferred tax assets | — | 
                                                5,91 9
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                4 , 256
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Non-current assets | — | 
                                                78, 545
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                7 6,210
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Current assets [abstract] | |||||||||||||||||||||
| Current inventories | — | 
                                                70 , 91 2
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                73 ,4 03
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Trade and other current receivables | — | 
                                                55, 2 88
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                59,039,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Cash and cash equivalents | — | 
                                                24,258,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                20, 8 8 4
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                31, 798
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Current assets | — | 
                                                150,45 8
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                15 3, 9 49
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Assets | — | 
                                                229,00 3
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                230,159,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Equity and liabilities [abstract] | |||||||||||||||||||||
| Equity [abstract] | |||||||||||||||||||||
| Issued capital | — | 
                                                6,806,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                6, 806
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Retained earnings | — | 
                                                6 8 ,095
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                70 , 2 0 5
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Share premium | — | 
                                                22 , 537
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                22,5 37
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Treasury shares | — | 
                                                1,833,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                2,194,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| 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
                                                    
                                                
                                             | 
| Liabilities [abstract] | |||||||||||||||||||||
| Non-current liabilities [abstract] | |||||||||||||||||||||
| Non-current provisions [abstract] | |||||||||||||||||||||
| Non-current provisions | — | 
                                                1 , 623
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                1,548,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Deferred tax liabilities | — | 
                                                4,452,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                2 ,1 0 5
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Non-current liabilities | — | 
                                                66,758,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                6 1 ,  424
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Current liabilities [abstract] | |||||||||||||||||||||
| Current provisions [abstract] | |||||||||||||||||||||
| Current provisions | — | 
                                                1 , 328
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                2,432,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Trade and other current payables | — | 
                                                34,5 89
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                36 ,2 18
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Liabilities included in disposal groups classified as held for sale | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                348,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Current liabilities | — | 
                                                41 ,1 6 5
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                4 4, 557
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
| Liabilities | — | 
                                                1 0 7, 9 2 3
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                105,981,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — |