Singletrackschool.Co.UK
I have been on a corporate day with them a few years back and also what they call their level 2 course with the optional guided ride in the afternoon last spring. For the elimination of bad habits for a general get out in the hills type rider I thought it was very good. Small group of us, good trails, a bit of banter and in my case a terminally bent front wheel.
My wife has just handed over another voucher for my birthday so I will be headed back at some point…
I also foresee a jedi day next year as I have heard such good things and suspect / hope from his reviews he may be able to view a cure a couple of riding blind spots for me with some personally focused tuition.