How do Sunday Interworking Patterns work on 6/22/24 and X21/26/66?
At a random guess I would think...
22 Durham To Sunderland - Sunderland To Durham - 24 Durham To Hartlepool - Hartlepool To Durham - 6 To Cockfield - Cockfield To Durham - Back onto the 22... PVR 9.

X21 Dar - Pet (09:57) - Pet - Dar - X66 Dar - Mbro - (12:25) Mbro - Dar - X26 Dar - Kemmel (14:14) - Dar (15:25) X21 Dar - Pet (16:57) - PVR 7.