Airways Flight Training Exeter, unlike the guy above I have nothing bad to say about them. Planes are old, the sim is old, the school has no toilet in it (short walk to the terminal) but you will receive unquestionably the very best quality flying instruction available in the UK and I've met no shortage of instructors. It was seeing them in action that I chose to change my style of instructing. I've not had a bad report and been thanked many times for sending students there.
(I have no reason for posting this, they don't give me discounts of benefits for saying nice things, they are just brilliant.)