We called the police and there's an incident report, so the insurance company will know what happened and Rob took lots of photos with his mobile phone so we have it all documented.
Luckily no one was hurt. It could have been worse, he could have hit us head on. That would have been bad. Instead the Z4 looks a little sorry for itself, but all can be fixed.
Thank you for letting me rant ... I just needed to get that off my chest.