Had some problems with this.
I think Ahmed24(site member) has also.
Advice would be to go for the obvious,its probably that.
After some experimentation,including going so far as jamming some cuddly toys behind the back seat and in the rear underfloor area , there was still a rear rattle that wasnt there when new .
I took everything out from the rear that was moveable including the rear parcel shelf(a previous suspect),spare wheel. jack n so on.
Rattle was still there.
It was the rear hatch.I could and still may get this fixed under guarantee but I wont be leaving it in for a service for 2 months at least and I wanted to fix it now.
I put some rubber household door draught excluding strips on top of the 4 points where the hatch is held closed .
This eliminated the rattle but it looked kinda bad.
I ended up using these
3 of them per side arranged in a triangle on the body contact area upper striking points
1 per side on the lower striking points.
The rattle really is gone for now at least.. tho there is a minor one up front somewhere !
This could probably be fixed by tightening the hatch locking plate ,but that has 2 large posidrive screws that are hard to get at..
Besides like Paul says door/hatch closing alignment adjustment is a real pia.
The "cheap car" noise is gone at last and I can allways remove the bumpon
bits before service.
Funny name, sounds more like some comedy film.