Is there maybe some issue with the pointwork or track circuits that is preventing 15 from being used as a through platform? However, nearly a week has passed since this topic started, so maybe not.
Perhaps someone has pee'd off the bobbies in the Bristol PSB▸ *?
*Power Signal Box. One for the Acronyms/Abbreviations page, Mods?
There is actually a problem with a set of points at the West end of platform 15 preventing trains from departing Westbound from P15. On Sunday night a Signaller forgot this and routed a westbound train into P15, set had to depart via Bristol East and pass back through the station again!