The rear cover can be removed in less than 30 seconds!
I had to do it to 'force' my warped rear cover back into place.
Unclip the sim-tray, and pop a paper-clip into the little 'tab' of the rear cover which shows through the tray slot.
Then gently ease the cover out and 'upwards' to unclip.
As above, the NFC & wireless charging antennae are stuck to the back of the cover, so you'll either need new ones, or you'll need to salvage them off your current cover.