Me and Roy did this last year and it was a really good weekend of trail riding round Wales with like minded blokes, and for a good cause, checkout:
http://www.advrider.com/forums/showthread.php?t=516896

Although there's a reserve list already, last event several dropped out as time went on, so there's still a good chance you'll get in ... what you waiting for .....

Will keep an eye on it Glenn. Looks like fun