I took my car in for a bit of work and as an extra bonus they appear to have disconnected the battery. Radio cassette is now codeless, and of course it's only now that I bother checking the documentation for the car and finding no code. Yes, I am an idiot. A trawl through this forum told me how to extract the radio and find the serial number, can anyone decode this for me?

It's a Ford Fiesta, radio is a 3000 Traffic and the serial is M050583.

Thanks to anyone who can help!