I did all my groundschool DL through Oxford but sat all the exams in Glasgow (just the way it turned out!). The facilities there are pretty good and I found that the small (ish) number of people in the exam room made for a quieter environment in which to sit the papers. In fact, for Flight Planning, I was the only person in the room!
The canteen at the Adelphi centre is good enough (and v.cheap to cater for the incumbent students)