I went to unlock my car earlier (Rover 200) with the remote central locking keyfob and nothing happened. I'm concerned to try the key in the door lock in case it sets the alarm off and am stumped as to what to do as I can't get the car anywhere to be looked at. I'm almost 100% sure it's not the keyfob battery as it has been working without hesitation until yesterday, when I last used the car. HELP!