Is there a special tool available to release the lock ring on the door pillar end of the wiring loom gaiter, I believe i have a broken wire in the drivers door but attempting to release the lock ring on the gaiter in the door pillar using a screwdriver and hammer simply stripped one of the raised sections, it is obviously VERY tight (or else it unlocks clockwise!). Currently the window is part open and I need to raise it as well as fixing the wire that stops locking etc.