Hi Jim
Ok, so here is the main diagram for the rear harness:
I haven't included the rear obstacle detection loom, as you don't have it fitted. So as you can see there is a right and left hand loom. These may be tied back into the one sleeve, but there are separate ones for the left and right lighting clusters.
As you can see these should terminate at the clusters in wiring plugs that you should be able to remove (just remember to label them up before removal as they'll surely become mixed up and you don't want to be having any electrical issues).
Getting all the plugs off might mean having to dismantle some of the trim to get at the heated window wiring, the third high-level brake light, the number plate wiring and of course the locking wiring in the tailgate.
The 'putting it back together again' episode may be a bit more of a challenge with threading the wiring, assuming you are replacing the tailgate.
