Further to CheekyChops post:
Taking the cheque to Abbey is clearly the only sensible course of action (but don't expect an immediate response because their counter staff almost certainly have a clue what to do about your enquiry).
However, your father's death certificate would probably not be sufficient documentation. You'll need an official copy of the grant of probate (if your father left a will) or of letters of administration (if he died intestate).
Further to Whickerman's post:
While a normal cheque might have a limited validity (even though I've managed to pay cheques several years old into my own account), the same might not be true of a 'counter cheque', which is actually a banker's draft, rather than a true cheque.
If it had been a normal cheque (drawn on a business or personal account) the drawer would get a big shock if Abbey suddenly took funds from their account after all this time. However the money came out of that person's (or business's) account over 10 years ago, and has been sitting in Abbey's suspense account ever since. They've no legal right to retain the funds, so it should be possible to pay the counter cheque to your father's estate.
Chris