On the saloon model if you climb in to the boot through the seats there is a plastic plug bottom centre on the door,inside it is a square hole that accepts a household door handle square rod so you can open the boot,I couldn't remove the lock even after taking the torque screws out so no further forward.I suspect either solenoid(I surmise it uses one)or broken wire at harness where cable runs from body to boot lid.Good luck.
Rich
May 2013