To remove the rear dor, you need to remove the trim around the switches, then undo the screw/s, not sure if there is one or two cant remembe lol. Next remove the door lock pin from the top.
Then the door is just clipped in, so carefully remove the door panel, now you will need to remove the soundproofing, best just to cut it away with a sharp knive, but not to much so it can be taped back up again.
Now you will have access to the motors etc.
Hope this helps
Paul