Code needed for ford raido (5000rds)?

Hi,

I need the code for my old radio from my focus (5000rds). I’m selling my car and have taken out the mp3 stereo, and now have to put back in the old one.
I can’t find the code anywhere.
I’ve had 4 attempts at it with various 4 digit numbers on ford paperwork but no joy.
The guys coming to collect on Thursday morning, so if poss, before then ;-)

The serial number is M161494

Cheers