Also check out the 'bigbikechallenge.co.uk'. It may be dot.com at the end!! This lists the Red Kite rally as one of there events.
I did the Red Kite rally last year and just made the big bike challenge on my XR650R. Personally wouldn't fancy it on my 1150GSA, although many did. I saw many upside down on the mountains, I'd be gutted on a 9k bike!