Echo India Mike's comments.
I've heard pretty good reports of Tayside and Leading Edge. With regards to L.Edge, it's run by a very very enthusiastic team who are very much in to aviation and you will be hard pressed to find a better team of dedicated British instructors at Leading Edge than anywhere else in Scotland. They have two new aircraft (PA28 Archer III) at both Cumbernauld and Perth and they are very, very nice indeed.