hi I brought a replacement remote for our p reg vectra. it is the right type ( model number and everything is exactly the same) however when we follow the programming procedure nothing happens the procedure we follow is :_ 1 start the ignition 2 press a button on the remote within 30 seconds 3 central locking clicks on to acknowledge programming is done. ( this bit just doesn't happen) is there something im missing? batteries are in the remote as the lights come on when pressed. all help would be appreciated.