I have used the central locking key to open and close my car doors but I purchased a spare key for my wife but it won't open the doors. I assumed that the new key may be at fault but I tried opening the doors with the original (central locking key) and that doesn't work either. I can get the keys into the lock but they won't turn, I tried spraying W.D. Forte into the key slot but that hasn't worked so any advice would be appreciated. Many thanks.