The message just reads err

Hi

The system is a Rover R660 Auto reverse, it's has an error message on it at the moment and I don't know how to clear it or put the code in. Any help would be greatfully received.

thanks

Just had car returned after having some work done - disconnected battery and now need routine for puting code into radio - don't have instruction manual. Can anyone supply step by step instructions, I have the code but don't know what to do with it. Thanks