Evening everyone. I’ve just brought an Audi RS6 on an 05 plate (will write up an introduction post after I’ve collected her on Tuesday) however there’s an issue with the stereo. As far as I understand the stereo was working well until the battery was disconnected for mechanical work. After reconnecting the head unit asked for its security code. The owner inputted the code however the unit does not accept it. The owner took the details from the side of the head unit and paid to have the code sent to him, thinking that the code he had might be wrong, however the code he received was the same that he had. Any ideas what could be the issue and ideas to resolve it please. Thanks for your help, Chris.