Hey, it's not super difficult, but it is a bit fiddly. Unfortunately I don't have time to post the pictures right now, but...
1] Remove rear interior trim (this is the black plastic piece that runs from side to side along the back wall). This piece is secured by the two rubber stops that the trunk hits, a couple of screws under "clip caps", a couple of tree-nails, and about 8 impact wedges. The wedges are what you see along the top edge - look like squares with a couple of indentations at each end. Pry these up with a plastic wedge, and they will pull straight out. This trim piece is wedged into the bottom sides of the car with a pressure fitting, it takes a bit of pulling to get them to release - pull straight towards the opposite side of the car.
1a] The boot light is on the left rear side of this trim, it's a clip fitting. Unclip this and the roof partition sensor switch.
2] Open the boot-lid side trim. This is the trim that covers the "arms" of the trunk, and looks like it has brushes along the interior. The rear piece "unclips", gently work the inside edge "down" and they will separate. Be careful, take your time. (I'll throw a picture of this..) After you have this clip released, you should be able to bend the trim piece up and out of the way
3] There are four bolts holding the lights on - three are easy to get to, the last one (outside, top edge) is a bit of a bear to get to. TAKE your time, if you drop a bolt, you'll never dig it out!
3a] The lights use a clip fitting for the electrical harness - again, it's pretty straight forward to remove.
4] Pull the lights out straight and level toward the rear of the car. Second picture shows where the scres fit in, and should help you find the bolt heads...
EDITED : Added pictures - who needs sleep?! ;P
