I had same problem, after absolutely no constructive help (it's an old radio/cass'-not the kind of thing thats stolen), from sites or Peugeot dealers, (wanted £15,more than stereo worth) I was looking through old dealer service receipts, on the printouts they have your vehicle details. Look for 'Fab No.' mine was 1141.
I have tunes again.
Hope this helps others.
Strange Ian
October 2009