I think this has sort of been cleared up already, however I was confused when looking at the live depature boards this morning...

the 0529 from Gloucester is now apparently due in to Westbury at 0707, with separate units coming from Bristol and splitting, one half to form the 0702 service which now apparently leaves at 0700 according to the live departure boards. So punctuality won't be completely demolished then, which is a plus... sort of. At least the morning northbound train is more likely to run now...

But I am still shocked at the way so many trains have been cancelled on the first busy day of the new timetable... transforming travel... (backwards)

And there's a good punctuality figure for the first busy day:
75% of services run

I'm also quite intrigued at the numbers present on the trains...