My son found this on a train forum. The 07.28 Stevenage to Moorgate is the 07.44 from Hertford. Think I'll give it a go.
HE51
5K02 05+32 Hornsey Depot to Finsbury Park
2K02 05.41 Finsbury Park to Moorgate
2F04 06.07 Moorgate to Stevenage via Hertford
2J30 07.28 Stevenage to Moorgate via Hertford
2V33 08.45 Moorgate to Welwyn GC
2K50 09.38 Welwyn GC to Moorgate
2F52 10.41 Moorgate to Watton-at-Stone
5J71 11+53 Watton-at-Stone to Watton-at-Stone via Langley Junction
2J71 12.11 Watton-at-Stone to Moorgate
2V73 13.20 Moorgate to Welwyn GC
5I00 14+14 Welwyn GC to Welwyn GC via Reverse Sidings
2K00 14.39 Welwyn GC to Moorgate
2F02 15.40 Moorgate to Watton-at-Stone
5J27 16+40 Watton-at-Stone to Watton-at-Stone via Langley Junction
2J27 16.59 Watton-at-Stone to Moorgate
2V28 18.00 Moorgate to Welwyn GC
2K46 18.58 Welwyn GC to Moorgate
2B48 19.55 Moorgate to Hertford North
2J63 21.00 Hertford North to Moorgate
2V65 22.00 Moorgate to Welwyn GC
5E65 22+58 Welwyn GC to Hornsey Depot
HE53
3B20 06+32 Hornsey Depot to Gordon Hill
2J20 07.11 Gordon Hill to Moorgate
2G22 07.55 Moorgate to Gordon Hill
2J38 08.41 Gordon Hill to Moorgate
2B40 09.25 Moorgate to Hertford North
2J57 10.30 Hertford North to Moorgate
2V59 11.30 Moorgate to Welwyn GC
2K72 12.28 Welwyn GC to Moorgate
2B74 13.25 Moorgate to Hertford North
2J89 14.30 Hertford North to Moorgate
2V01 15.30 Moorgate to Welwyn GC
2K18 16.28 Welwyn GC to Moorgate
2G25 17.25 Moorgate to Gordon Hill
2J37 18.12 Gordon Hill to Moorgate
2G40 18.55 Moorgate to Gordon Hill
5E89 19+42 Gordon Hill to Hornsey Depot