Have you tried unplugging the box from the mains and then plugging it back in again?
Also reinserting the card might convince it that there is actually a card in.
Not that it really matters if everything else works, but it might be the sign of a software fault on your box, if it still doesn’t give a card number you could try a software upgrade (but beware of loosing recordings when doing that).
@Polomint The Box is brand new (1week old) as my old Amstrad packed up and Sky replaced it with a New Grundig which was installed by their engineer who did the usual ringing to sky and giving them the details and activate the card. Still as everthing works o.k. I will leave it alone.