Having just had to pull off my rear bumper to refit it where it had been popped off I thought I'd put up some piccies of the process.
The bumper is held on by two bolts under the taillights, four screws underneath the rear tailgate and clips on the leading edge where it connects to the rear quarter panel. Removal procedure goes something like this:
Remove mudflaps, unscrew bumper from brackets that attach underneath the rear bumper.

Remove rear flares to access 2 nylon clips that are underneath at each side



remove taillights and disconnect harness for reversing sensors (after disconnecting battery first) Remove two bolts retaining bumper.


The tread on top of the bumper just unclips and allows access to the nylon clips that hold the bumper under the tailgate.It isnt necessary to remove the large plastic screws under the tread, these hold the foam visible in the shot below

You can just make out the hole for the nylon clip to the left of the hinge in this shot, there are 4 of them under there. the attachment points on the bumper are visible in the shot above



After removing all the retainers you should be able to pull the bumper backwards away from the rear of the vehicle.



When reattaching the flares it is necessary to refit the clips that hold them on, they are in two parts and seperate rather than pulling out of the sheet metal. Just carefully use a flat bladed screwdiver to remove the part retained in the hole and clip them back together, attach to the flare and push home in the bodywork. a close up of a seperated clip is below.

It took me about three hours to remove and replace but I'm sure it would be quicker next time.
Regards,
Tote