Statement Of Cash Flows [Abstract]
| Concept | 2024-04-01 to 2025-03-31 | 2024-04-01 to 2025-03-31 | 2024-04-01 to 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 | 2024-04-01 to 2025-03-31 | 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 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of cash flows [abstract] | |||||||||||||||||
| Cash flows from (used in) operating activities [abstract] | |||||||||||||||||
| Profit (loss) | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                1,0 40
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                1 ,04 0
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                4 , 4 4 0
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                4 , 4 4 0
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
| Adjustments to reconcile profit (loss) [abstract] | |||||||||||||||||
| Adjustments for income tax expense | — | — | — | — | — | — | 
                                                3,888,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                3,651,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Adjustments for finance costs | — | — | — | — | — | — | 
                                                3, 758
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                4, 8 93
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Adjustments for decrease (increase) in inventories | — | — | — | — | — | — | 
                                                1, 629
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                14 ,9 77
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Adjustments for impairment loss (reversal of impairment loss) recognised in profit or loss | — | — | — | — | — | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1 ,476
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Adjustments for provisions | — | — | — | — | — | — | 
                                                1,0 30
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                900,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Adjustments for unrealised foreign exchange losses (gains) | — | — | — | — | — | — | 
                                                90,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                24 8
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Adjustments for share-based payments | — | — | — | — | — | — | 
                                                426,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1 01
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Cash flows from (used in) operations | — | — | — | — | — | — | 
                                                19,0 63
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                31,9 11
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Income taxes paid (refund), classified as operating activities | — | — | — | — | — | — | 
                                                2 ,1 6  8
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                3, 335
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Cash flows from (used in) operating activities | — | — | — | — | — | — | 
                                                16,895,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                28 , 576
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Cash flows from (used in) investing activities [abstract] | |||||||||||||||||
| Proceeds from sales of property, plant and equipment, classified as investing activities | — | — | — | — | — | — | 
                                                292,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                91,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Dividends received, classified as investing activities | — | — | — | — | — | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Interest received, classified as investing activities | — | — | — | — | — | — | 
                                                283,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                265,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Cash flows from (used in) investing activities | — | — | — | — | — | — | 
                                                2 , 2 15
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                23 5
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Cash flows from (used in) financing activities [abstract] | |||||||||||||||||
| Proceeds from issuing shares | — | — | — | — | — | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                8,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Repayments of borrowings, classified as financing activities | — | — | — | — | — | — | 
                                                —
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1 1 6 , 5 0 0
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Payments of lease liabilities, classified as financing activities | — | — | — | — | — | — | 
                                                4 , 4 0 4
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                3 , 362
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Dividends paid, classified as financing activities | — | — | — | — | — | — | 
                                                2 ,426
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                3, 02 6
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Interest paid, classified as financing activities | — | — | — | — | — | — | 
                                                4 , 6 7 2
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                6 ,702
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Cash flows from (used in) financing activities | — | — | — | — | — | — | 
                                                10 , 873
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                3  8 ,1 6 8
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Increase (decrease) in cash and cash equivalents before effect of exchange rate changes | — | — | — | — | — | — | 
                                                3, 807
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                9, 82 7
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Effect of exchange rate changes on cash and cash equivalents [abstract] | |||||||||||||||||
| Effect of exchange rate changes on cash and cash equivalents | — | — | — | — | — | — | 
                                                433,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1 , 0 87
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | 
| Cash and cash equivalents | — | — | — | — | — | 
                                                24,258,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                20, 8 8 4
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                31, 798
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             |