Thank you both, I have contacted the seller of the piano and they have contacted casio for me. I will see if they have any ideas - bit gutted as I treated myself to lots of new music books only to have the piano refuse to work! Honestly I am not that bad on the piano! I will update.
Small update - Casio will take the piano back but I have to pack it up - trust me to have thrown away the box! I don't have boxes the size of a keyboard just lying around! This should be fun to arrange.