I did the Cycleactive Mountain Skills course August Bank holiday 2007 and definitely improved in confidence & ability. Really enjoyed it.
Well, I say that but 3 weeks later when my full suss Genius (which I’d done the course on) was in for a service I was riding my 1995 GT Tequesta with approx 30mm of front squish. Out with my mate on his Patriot. Feeling full of confidence on a rocky downhill bit I raced past him and… broke my collar bone. Hum.
I also did their Trials to Trails course August Bank holiday 2008 with Ritch Barnard and that was great too, and the evenings are good as well. Very good rider & a really good weekend. If you do it though, make sure you make notes each evening else you’ll forget all the little steps leading up to the skills.