| B Final | |||||
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 2 | William Cole | 18 | Co Bristol | 56.02 |
| 2 | 3 | Edoardo Valsecchi | 20 | Plymouth Lea | 55.42 |
| 3 | 4 | Reece Dunn | 22 | Plymouth Lea | 55.23 |
| 4 | 5 | Matthew Domville | 20 | Warrington W | 55.17 |
| 5 | 6 | Jacob Jackson | 19 | Ellesmere Co | 55.18 |
| 6 | 7 | Jamie Ingram | 19 | Co Manch Aq | 55.27 |
| 7 | 8 | Freddy Clampett | 19 | Plymouth Lea | 55.69 |
| 8 | 9 | Cameron Brooks-Clarke | 18 | Co Sheffield | 56.03 |