If you want to just replace the bulb, you may be able to do that by removing the panel inside the rear of the rear wheel arch. This has nut at the top and a screw at the bottom.
If you want to replace the whole light unit, then you probably have to take the bumper off (at least that's how I've just done it).
To take the bumper off, open the boot and undo four screws along the top edge of the bumper.
Next pull out the two fasteners along the bottom edge of the bumper. (These fasteners have a pin in the middle which must be pulled out first.)
Then undo the screw inside each rear wheel arch at the bottom. (The rear wheels get in the way a bit, but you can do it without removing the wheels.)
Next undo the nut securing the end of the bumper to the body inside each rear wheel arch at the top.
Carefully unclip the body trim panel from the front edge of the bumper and you should then be able to remove the bumper.
To remove the light unit, simply undo the one screw on the inner edge.
John Waller, January 2006
