I have noticed lately that my central locking is playing up. Some days when you hit the button on the key to open the doors, the drivers door does not completly unlock, you have to reach in through the back door and finish the job. Other days it is the passenger front door. Also sometimes when you close it, the lock does not go all the way down even though it has locked. Could it have something to do with the battery in the key? Any help appreciated.