PGL look good. Web is
http://www.pgl.co.uk. Haven't been yet but got their brochure - am sure I've read posts here from people who have been. They have a site in Shropshire, 2 in Scotland and the rest south of England, Isle of Wight and France. Loads of activities - canoeing, archery, oreinteering, mountain biking etc. Am hoping to go next spring as well.