Well there's a lot of slack in the HSS▸ timetable at the moment as IETs▸ can make up a short hold, station pathing depending, so control might be a bit more willing.
Add the summer holidays with a lot of changes made at Westbury between north-south to east-west and vice versa, and a 2 hour wait means either busing or taxiing a lot of people.
Expect that to change again come the December timetable.
Indeed - although we grumble about current service robustness / reliability, there is potential for the December changes to compromise what standards we have at present on the altar of speed of journey.
GWR▸ 's "how do we make station stops quicker" question of late July rather indicates they are wise to this potential.