Needing a lock diagram...

Hi guys, the tale of woe continues with my Disco (Mk 1, 300 TDI). Yesterday after putting my dog in the back and bombing along the back roads I turn the corner and my tailgate door swings wide open, luckily the dog stays in but still gave me a bit of a shock. Needless to say there's something buggered with the lock, the little spring on the outside handle is fine, it's even had a drop of WD40. The problem is the latch (on the door)which connects to the 3/4 inch thick pin, it seems to have turned 180 degrees so instead of having an opening to latch on and lock to the pin it now just bounces off making it impossible to close the door properly. I've now gutted the inside, taking off the inside door opener and some of the other stuff but I still can't figure out what's broken or gone wrong . I've twisted, prised, pulled, and levered and somehow manges to move the latch round so I can at least close and lock the door. Any ideas what to try now and does anyone have a link to a detailed diagram of how the lock is assembled? Cheers for any help. BTW as bad luck would have it the remote lock on the tailgate has gone on my other Disco (Mk 2 TD5), is it the same accurator as the Mk 1 300 TDI or a completely different beast?