EVENT 304 Open/Male 12 Yrs/Over 400m IM - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 2 | Luca HALLAM | 12 | Grantham | 6:29.01 |
| 2 | 5 | Francesco MONACO | 12 | South Lincs | 5:54.49 |
| 3 | 7 | James THOMAS | 14 | Gainsborough | 5:41.31 |
| 4 | 9 | Ben CARLYLE | 14 | Grantham | 5:34.02 |
| 5 | 8 | Oliver GARNER | 14 | Co Lincoln P | 5:34.82 |
| 6 | 6 | Charlie BISBY | 13 | South Lincs | 5:46.70 |
| 7 | 4 | James HUCKLE | 13 | Lincoln Vulc | 6:04.43 |
| 8 | 1 | Samuel NICHOLS | 12 | Grantham | 6:37.91 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 11 | Daniel HEPPLESTONE | 14 | Co Lincoln P | 5:28.32 |
| 2 | 14 | William VERE | 15 | South Lincs | 5:23.78 |
| 3 | 17 | Archie FRENCH | 15 | Lincoln Vulc | 5:23.50 |
| 4 | 19 | Evan NOORPURI | 17 | Lincoln Vulc | 5:23.31 |
| 5 | 18 | Jack HICKS | 15 | Lincoln Vulc | 5:23.46 |
| 6 | 15 | Benjamin DERBY | 16 | Lincoln Vulc | 5:23.63 |
| 7 | 13 | William TAYLOR | 16 | Louth | 5:26.83 |
| 8 | 10 | James CASH | 14 | Deepings | 5:33.49 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 21 | Leon BAILEY | 18 | Louth | 5:18.98 |
| 2 | 23 | Ryan NORTON | 17 | Boston | 5:04.49 |
| 3 | 26 | Thomas BRUCE | 18 | South Lincs | 4:56.99 |
| 4 | 28 | Rico BRINGEMAN | 19 | South Lincs | 4:38.10 |
| 5 | 27 | Oscar GOLDSMITH | 16 | South Lincs | 4:49.29 |
| 6 | 25 | Jacob FISH | 15 | Grantham | 5:00.07 |
| 7 | 22 | Zach HOPKINSON | 15 | Grantham | 5:09.53 |
| 8 | 20 | Jacob BRIERS | 16 | Deepings | 5:20.10 |