Freelander rear door problem

Any one heard of this one. My mate's wife has a '99 Freelander diesel. Just recently the central locking has started "chattering" and to her horror, the rear door lowers its window fully, and the door swings open whilst in transit. The rear door should lower its glass by an inch when you are stationary and opening the rear door, not fly open while you are moving. My mate has disconnected the electrics and tied the door shut. He phoned Landrover who want a phenomenal amount of money to fix it. He reckons it's to do with some microswitch somewhere, the only hint Landrover gave him, but he can't find it in the rear door. Any one come across this problem before or know where the microswitch is, or experienced the same thing? I reckon this should be up to Landrover to fix as it's a safety issue. You don't expect any door to be able to swing open when you are on the move.