Hi,
I would suggest doing the ground school with either CATS at Cranfield or Bristol Groundschool - both are excellent.
For the post-PPL flight training it really depends what you want from your school & instructors. If you like to be another sausage from a sausage factory then use Oxford / Cabair / etc.
However, if you want your training to be more tailored to your own needs and aims I would suggest you talk to David Coulson at Cranfield Flight Training - OK, so he's a tough old yorkshireman but in all my flying, both training and as FO and now Capt, he is still the best instructor I have ever flown with (and I've flown with a few !). He doesn't work to a fixed training timetable and rather teaches to match the streghts and weaknesses of the student - very flexible !
Anyway, thats my tuppence worth...
Good luck,
Ian.