The fault I had with my twindoor was that neither of the boot lid buttons would work and the only access I had was boot not hatch and only via the remote, after much fumbling and stripping down I discovered that the fault was broken wiring which runs through the left-hand side of the boot/hatch via the hinge to the roof of the car, there were no fault codes showing on VCDS.   Once you understand it the twindoor system is not complicated, the main components are the usual centre mounted centrally