Hi,
Generally, the death of the Debtor discharges his liability of repayment under section 75 of the Bills of Exchange act upon notice being provided to the bank. It appears that you may be liable for repayment of the debt as executor or representative due to not providing notice, however this depends upon the precise merits and due to the vast scope you should seek the advice of a solicitor. Various options if you are rendered liable are to argue that the contract is frustrated, or indeed if the loan was executed post April 2007 to check that it is in fact enforceable under the Consumer Credit Act. Hope this helps.