Review your calculations. OAA is £1225 initial payment plus 2 periods of 2 weeks each at £300
per week. So it makes total of 1225+2*2*300 =2425£.
These are 2011 fares, so they may increase them next year. For you living SW of UK, I'd bet you choose Bristol. For me, having to take a international flight to go to the lectures, Oxford is far better (also, IMHO, they provide better notes
).