Glasgow tends to get mixed reports in my experience. People I know who have gone say its pretty poor, but some folk here say they're ok. Certainly when i visited and saw their notes I didn't go. They were appalling.
If you're going D/L I would say you can't go wrong at Bristol. You won't hear a bad word about them anywhere, they are excellent. If you are from GLA then the extra you would pay going to Bristol for courses (4 weeks) in accomodation would, in my opinion be a wise investment at such a crucial stage. It only works out at about £400 tops - just over an hour in a twin!!!
I would add that I was able to attend full time, but felt I would do better with Bristols material studying at home - it is that good. And I never waited more than three hours for a reply to a question.