I need code for radiocasette FD2500 series M019080 (Ford Fiesta)?

I own a Ford Fiesta 1300cmc produced in 2002.
Last week a mecanic took away the wires from battery.

So, now I need the code to unlock radiocasette which is model FD 2500, serial: M019080

I am the second owner as I bought the car in 2004 from Germany and never asked the first owner to give me this code.

Please help. Thank you.