You may also find this diagram of front door handle and lock parts from Rimmer helful http://www.rimmerbros.co.uk/Item--i-GRID004316
Malc
February 2010
I am also trying to fix this on my MG ZT and have found the following forum item useful http://forums.mg-rover.org/showthread.php?t=298216&highlight=front+passenger+door+lock+stuck
I have managed to remove most of the door card (still attached by the single inaccessible screw at the front) but access to the lock mechanism is very limited.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cars.