John,

I'm assuming your problem is the lever latching mechanism on the inside door face. The latches are anything but sophisticated so you should be able to fix. If not.....Is this yours?

http://www.westonbodyhardware.com/portfolio_item/d26-hook-latch-remote-operated/

Hope this is of use.

Regards

Geof
70th Anniversary 4/4 (Duratec 1.8), model 1995