go to www.ukskydiver.co.uk/cms- it is the national UK skydive forum and it has a forum for every DZ in the UK inc Black Knights. there you can ask loads of questions and get your answers ;)
Only been there once, for an 8-way competition that no other teams turned up to.
So the meet was a washout, but the DZ itself was great. Lovely people, beautiful views, nice plane (although not for 8-way!) Can't speak for their AFF programme, but I guarantee at least that they'll make you feel welcome - and I should imagine from their general attitude that it's a good place for a student to train.