I too have been hearing strange noises from the rear (!) and have tried to figure out what is going on. I removed the parcel shelf because that is what I originally thought would be the cause but that made no difference.
On closer inspection, I noticed that from the back seat with the parcel shelf removed I could see daylight through a gap between the rear hatch and the seal (when closed). I then noticed that from the outside, the rear hatch is significantly misaligned and that the side with the gap moves substantially when pushed. I managed to stop this movement by unscrewing the bump-stop thingy a little, but I think the noise could still be there although it could be the parcel shelf because one of the clips has broken.
Anyway, I've contacted a dealer near to where I work and after taking my chassis number they have ordered a parcel shelf clip for me and when it arrives in stock, they'll have a look at aligning the tailgate, fixing the rattly headrest, attaching the drivers door electric window switch panel to the trim properly and sorting out the problem with my Bose system. And theres the passenger side rear door not only makes a funny noise when shutting it but doesn't seem to shut tightly