Try your local Ford dealer, give them the registration number and find the vehicle identification number VIN on your documents and give them to the dealer. As long as it's the ford fitted radio they will (for a charge) get the number for you Good luck
You normally have to show a ford dealer your V5 doc to prove ownership. The other option is to check the yellow pages for a local car audio shop - normally they will re-code a stereo for a small charge.
I had the same problem a number of years ago. If you have the log book, this will tell you who the original dealer was.
Phone them and they should have the original code on record.
It worked for me and they didn't charge.
You can unlock your ford stereos using just the serial number of your radio ! you can phone 0845 838 2378 or visit www.carradio-code.co.uk they will unlock the radio over the phone with you.