Lost keycode for my Ford RDS 2006 car radio?

I asked this question a few days ago after my battery died and the radio lost power. I was asked for the serial number (by RegWorts) in order to generate the correct key, which is M199394.

Thanks in advance for any help you might be able to give me on this and thanks to RegWorts for pointing me in the right direction with the serial number.

Regards, Damien