Try Cleveland Flying School .
http://www.clevelandflying.co.uk/ Tel 01325332855.
I've had no problems with them (currently doing my ppl), and they have a relaxed, laid back atmosphere. The other alternative is St Georges Flying School, I dont know much about this club. These are both situated at Durham Tees Valley, best thing to do is give them a ring and have a walk round and maybe talk with a few of the instructors in the bar. Good Luck with your flying Mate.
Jon.