Well...it had to be something simple and tomorrow I find out if this fixes the problem....

I hadn't noticed but the new ring gear I'd installed to the pressure plate didn't have the 3 holes drilled as highlighted in the attahced photo.

After pulling the drill press out and drilling them in I can see the pressure plate will now disengage properly.

Thanks heaps to everyone who has offered their assistance.

http://forums.pelicanparts.com/uploa...1150552492.jpg