I had the rattle from the rear on the N/S - simple fix.
I took the parcel shelf off and no noise. I figured the parcel shelf connectors on the shelf must have become worn over time resulting in some play which caused the creaking. I put sone electrical tape on the cylindrical tabs that the shelf snaps onto (near to rear seats) and the car is now silent! I tried doing just the N/S but that transferred the noise to the O/S so I wrapped both sides which created an equilibrium. It did creak when I opened up the rear hatch but that disappeared after a few days and now all good - completely silent. I used black tape so you can’t even see it if you take off the shelf - the tape is about the same width as the tabs. I used about 20-25cm per side.