I've just text my mate who uses an instructor called Katie Barr - thinks she's fantastic. In fact the result of their lessons is that my friend has qualified with my irish cob for the Scottish Farmer Dressage Championship at Rowallan
Mate not sure how far she travels - I think she's in Lanark but if you want to pm me I can give you my mates email and she'll forward you contact details etc.
I get fortnightly lessons from Erik McKechnie at the yard im at in Edin and Linda Penman also comes to the yard to teach i know they both travel alot as Erik is based in Gleneagles
Not sure of many more but i know SNEC hold dressage clinics if that helps
I second Katie Barr, best flatwork instructor ive ever had. Not sure how much she would charge as im not sure how far she would have to travel but I pay £25 for 45mins and she has to travel about 20mins to us but teaches 2 at a time.