The two clear plastic covers of the lamp-holders (on the tailgate type of rear door) are clipped in place on either side, and not screwed. Small internal preojections on the covers engage into flimsy plastic catches on the lampholders. Be prepared for at least one of them to break as you gently prize the covers off with a screwdriver. (I glued one cover back in place effectively to a broken catch with hot-melt-glue). The bulbs are not bayonet or screw fitting but are of the plug-in type. The old bulbs just pull straight out. Due to access difficulties it is advisable to remove the cowling above the lamps. It is secured with three 8mm nuts on the inside of the door. First remove the door back panel which can be mostly prized off, but there are four screws to undo: two on each handle. The cowling nuts can be accessed through holes in the rear metal panel of the door. They are blanked off with clear foam plastic. The middle nut is behind the R/H side of the wiper motor.
You will need a long-armed socket set with 8mm socket and torx screwdrivers of small and medium sizes to carry out this work. Do test the bulbs before putting this lot back again. I had a new bulb fail within seconds of fitting. The whole job took about 2 hours.
Steve the frustrated rear numberplate bulb fitter.
August 2010