Jasper, its possible to have the boot open as a hatchback all the time, it was a case of having too with me, my boot wouldnt open at all, mainly the two wing motors wouldnt release, so I took them off, but this involved a bit of work to be done from inside the boot to release the pin that the motors cling onto. once thats done and the boot is opened as a hatch then pull out your wing motors, they only have plug in electrics and held in with 4 screws. but I since discovered my problem with the boot not opening, its the wiring that runs through the arm of the sedan part of the boot were pinched. I've since put it all back together and happy to have a twin boot again.
but YES you can have it as a hatchback only.