Ok so update on my one as it has the electric power open / shut tail gate.
The rear plastic inner cover will pop off (no screws or fixings) but you need to be a bit brave for the initial bit.
My one has a latch and also a separate larger motor unit above it which once the boot lid closes pulls it shut tight this links to the latch via a pull cable.
I took the cover off just to confirm part numbers and to prove the manual release should the release on button fail completely.
Since this the boot has behaved itself so i suspect there may have been a dead spot on the commutator of the small 12v dc motor that operates the release which has fixed itself due to numerous operations of the boot over a couple of days..
I have ordered what appears to be a direct replacement for the motor from ali express and will inspect and test when it arrives see pics below from website, search "1Pcs For Volkswagen Eos CC Jetta Tiguan and Passat B7/CC Car Trunk Lock Actuator Latch Release Door Lock Motor Accessories Auto" or the number on the top of the motor and you should be able to get the same, for some reason I can't directly link the specific one I ordered sorry.
I'll attach some pics I took of the boot with the cover off later (cant do it at work).
As and when the boot becomes problematic again I'll have the motor and should be able to do a swap out.