I started of at Bristol but moved to Orbit Ground School in Arnhem, Netherlands last year. Main reason for me was Orbit Ground School being a lot closer than Bristol. I live in Germany.
At Orbit they can arrange exams for you with most of the EASA CAAs. Belgium is pretty cheap. That's what they normally suggest to foreign students as it seems the CAA in Belgium has least bureaucracy.
All 14 exams are 440 Euros in total. But you have to write them in 2 Blocks, each Block split in 2 days within 1 week. Bloc A Day 1Flight Planning 2 hrsMass and Balance 1 hr Performance 1 hr Bloc A Day 2General Navigation 2 hrsRadio Navigation 1.5 hrsPrinciples of Flight 1 hrHuman Performance 1 hr
Bloc B Day 1Aircraft General Knowledge 2 hrsInstrumentation 1.5 hrs Air Law 1 hr Bloc B Day 2Meteorology 2 hrs Operational Procedures 1.15 hrsVFR Communications 0.5 hrIFR Communications 0.5 hr
You can start with Block A or B it doesn't matter. Just the subjects can't be moved around. Hope this helps.