how do i enter my car???

I have a Rover 214si and twice have not been able to get into my car due to the keyfob not recognising my car resulting in me paying for the car to be towed to a Rover dealer and having the keyfob programmed to my car again! The dealer has told me my car is too old to have a keycode which overides the fob thus abling me to at least enter and drive my vehicle, is this true??? My rover is a 'N' reg on a 96 plate..