unless she had payment protection, her estate will be liable for the bills, so if she has any money or assets and has left a will, the credit card balances will be taken out before her estate is divided as per her instructions
if she hasn't left a will then the money will be taken from her estate before being given to her husband/ shared by dependents
but in all cases (don't know if your gran was rich, comfy or just treading water) the priority I believe is for funeral expenses, so if you forked out for that, you have first claim.
Thanks to you all it is a worry for my parents and my husband and myself are just trying to find out legally where they stand. Someone said that as she has died it is an debt that could be written off but I am sure we are not that lucky!
The thing to remember is that you personally are not liable for the debt - she in the form of any money or assets she left, in other words her estate, is.
If there is enough money to pay the debts, then they have to be paid. If not. they have to be written off. There's an order of priority for debts - basic funeral expenses and taxes take priority, then unsecured debts such as credit cards.