2010 Focus internal door trim removal.

[CasaDelTuco]

Hi All,

The rear passenger door of our Focus will close but not lock. The lock lever above the door release stays in the 'in' position and when pulled towards the passenger it just pops back in towards the door.

I've taken the door cover off but there's yet another metal cover.
Before I jump in and bugger up the motor gears for the window I want to ask if there is a procedure I should follow to disassemble the door to get to the faulty bit which I'm guessing is near the door latch.

While I'm asking does anyone know what part is broken?

I tried to add a photo but it wants it uploaded to a web site first. Not sure how to do that however the picture is of the door with the plastic bits removed and a silver metal cover over the window working bits. Looks like the window motor is a white plastic thingy. There are quite a few bolts / screws etc but I don't want to undo the wrong ones in case it doesn't go back together.