Silsoe is the Best
I've been to oxford & Silsoe and Silsoe is the better of the two. Additionally I have spoken to other students who have been to Gatwick & Silsoe and they recommend Silsoe.
Oxfords on-campus accomodation is appalling and the food is even worse.
Silsoe is good because you are in the middle of rural befordshire excellent on-campus accomadation 2 mins walk from the venue, and the food is a little better.
Gatwick I believe is a hard work, the B&B's are quite a distance form the venue the traffic can be horrendous in the morning as too with finding a parking place.
If you like to sit in exam halls on your own then Glasgows for you!!