Mine works beautifully, and I use a lot everyday, but mainly I use the inside button and the key button to open. Just hope you are able to close it from the key, not only with the trunk and driverside door button.
I'd been thinking that that "clever camera mechanism" was an incident waiting to happen. No moving parts is (usually) fine, as soon as you stick in something mechanical to make it extend/retract it's a potential cause of problems.
I believe from the manual it allows you to open the tailgate from inside.
Undo the warning triangle holder, move it out of the way. There should be a slot where you can insert your key (it shows the key but perhaps any suitable metal bar small enough to fit (screwdriver etc) would suffice.
Slide this over to the left (looking at boot from inside) to unlock.
My rear view camera recently failed to work. Opened the boot manually and it now works again. However I'm not sure the badge is fully opening as I can see the lip of the car along the bottom of the picture. Can't for the life of me remember if it was like that before! Can anyone let me know if their view also shows part of the car in the image. Thanks.