Why AFT when 50 metres away is a first class FTO?
Main point to bear in mind if you train at Coventry is that the IR is done at Leeds so to train on the routes and airfields for the test you've got a lot of transit time.
Wheras at Bristol you are ideally located with a local examiner and can pack a lot in to the training. Another benefit is that you'll be mixing it with commercial traffic which is good training.
Personally I rate BFC very highly and they have a very good pass rate. Pop in and have a chat with them and speak to the students and instructors, you'll not be disappointed.