How do I remove the Blaupunkt radio/cassette player?

I have a Blaupunkt radio/cassette in my Fiat Brava, unfortunately I had a flat battery and I lost the use of the radio/cassette player - I have also lost the code to 're-program' it. How do I go about removing the player to access the serial number? I have already tried to prise the fascia but with no luck. Any ideas? Thanks.