In reply to Edd Reed: Thanks for all your replies, I have managed to source a guide book at Hitch N Hike in the Peak District;
http://www.hnh.dircon.co.uk/
They don't have any Mournes guides, just thought I'd ask as they are also out of print. It does look like the MCI are looking to republish the Mournes guide, perhaps this is why all the other info has been removed.
Thanks again
Edd