Peugeot 307?

I have a peugeot 307 and the radio died. I got another on eBay and all is well...except that it beeps every second very loudly. I am told that it needs "marrying" with the car but the local car radio place can't do it and Peugeot won't do it unless I can provide the chassis number of the car it was originally from...which I can't.
Any ideas how to get round this issue??