Tewkesbury to STRS isn't a biggie. Two of my son's friends do it every day with no problem. However, they use Bennetts coaches so it would only be a single bus to and from each day. Of itself that's no problem but at all other times, you would be looking at taking him. With Elmbridge now improved, nipping down the motorway isn't too bad a journey (accidents permitting).
For Crypt it would have to be Stagecoach you would be looking at the 71 stagecoach (
https://bustimes.org.uk/services/swe_45-71-_-y10 (every 30 minutes) and then the 10 (every 10 minutes) as I don't think any coaches run there; I could be wrong though. I must say, I wouldn't put my ds through that each day.
Wouldn't know where to begin with travelling to Pates from Tewkesbury so can't help there.
As has been said, a carpool is also good, although remember you would have to take your turn as well.
You should also consider cost of transport. My dd used to go to Ribston and it was about £1000 per year. Stagecoach would be far less than that.
Ref tutor, personal choice. If he is coping OK with what your are doing, I would persevere. Loads of very broad reading and Synonym Toast (fab online game) and maths problems off the net are good. We knew our ds wouldn't work well with a tutor regime so we did DIY which worked well for us.
Mock exams for us were invaluable.
Looking at your situation I would definitely try for tommies (my ds loves it there), subject to what I've said above. Logistically, I think that is the easiest.
Bullying goes on in every school and anyone who says different is deluded I'm afraid. Kids can actually be not very nice people at all. It's how the school deals with it is the key.