Thanks for advice Chimney.
Im a hardcore road runner really and ive only just started venturing into the world of off road running in the last couple of months. Ive picked myself up a pair of Mizuno wave ascend 6 shoes and im quite pleased with them so far, they seem to cope quite well on tarmac/gravel as well as they do on mud.
Thanks again, should be a good race by the sounds of it!