Thank you for your question
My name is Clare
I shall do my best to help you but I need some further information first
How much has gone from the account that is not accountable for as necessary spending
Your mother was in hospital that entire time?
So could not have indulged in shopping trips?
What you are talking about is potentially criminal fraud.
As a starting point you should report the matter to the Office of the Public Guardian
If they cannot deal with the matter then you need to report it to the police.
You may also wish to consider applying to have her removed as Executor on the grounds of her failure to give a proper accounting of her actions.
Please ask if you need further details