I'll second the "you lucky ****"!!
Have you asked any Rover dealers whether they have any old manuals? Failing that, try the MG Cars group website:
www.mgcars.org.uk
and snoop around there. They have a forum/BBS and classifieds, so hopefully you'll find either what you're looking for, or someone who can suggest other places to look.
Good luck with the manual, and post some pictures SOON!