How do you unlock the Stereo on a Vauxhall Corsa? ?

I have just bought a Corsa. Unfortunately they removed the battery when doing some work for me so they have locked the stereo and for the life of me i cannot unlock it. I have the security number but have no idea of how to enter it, the number also has a digit 8 in it and my numbers only go up to 6. Can anyone help with this because it is driving me around the bend? The corsa is an 03reg. Many thanks

Larnsey
April 2010