All going from dalton park to sunderland via Seaham (apart from the 265). The x7 isn't much of an alternative with it being hourly, which is why I think it would be best suited avoiding Seaham and duplicating what is already running between Seaham and Sunderland Inc the new bus replacing the 203 (can't remember number).

If the x7 was to call at Dalton Park and then go along the A19 to Doxford Park, surely it is extending the untapped Market, like it does south of Peterlee? I can see that bringing more passengers Inc. Commuters, than the route it is using via Seaham.