A small point, which applies to all of the "solutions" linked above, is that replacing the standard incandescent bulb in the boot with a basic led equivalent will result in the led being dimly lit, even when the hatch is closed. Certainly not enough current draw to be a problem for the car, short term anyway, but not as it should be. I have seen suggestions that fitting a "canbus safe" led bulb will fix this, but I have no proof of this, or examples of suitable bulbs.