You may find a good instructor or riding school if you ask around the Horse and Hound forum, as that one is more British than this. I've gotten some advice from them on instructors around here when I got my OH to take a video of me riding and the result was "Holy sh****! I suck!" I haven't gotten round to finding knowledgeable eyes on the ground, but at least I know who to look up if I ever do.
My horse is about an hour from Edinburgh. If you're ever in the Central Belt for a wee visit, drop us a line. :)