Correct, from East Coast IEP Agreement Page 166
Reading isn't ideal as the staff base is guards, TMs and catering staff, no drivers. Full list of XC driver depots
here.
Out of the 14 'spare' (if 175s come) 802s, about 10 in service would be reasonable, assuming GWR don't need any additional 802s. That isn't enough for Plymouth - Edinburgh, and that route has a few driver changes so quite a lot of staff would need training.
Bristol - Manchester 1tph is doable and would only need staff training for Bristol (Birmingham can do Birmingham - Bristol but moving units out of the depot would be difficult without a nearby driver depot) and either Birmingham or Manchester. But its currently set up to interwork with the Manchester - Bournemouth...