If I spot BuenChico I will point him here
he has a handful of sites which tell you what to do on a death
I would get a the top copy of the will to be honest
a bank doesnt need to store it
and when he dies - you have to wind up the estate
here is one site to start you off
https://www.gov.uk/after-a-death/overview
Your difficulty only is if a lawyer or the bank have insisted they are also executors and then you are in their money grabbing hands - they can go slow and charge a bomb ( £200/h ). Oh and you cant fire them as executors
This would have been better under Law - Civl but you have had a few andwers from the usual suspects ....
and this doesnt look too bad
https://www.citizensadvice.org.uk/relationships/death-and-wills/dealing-with-the-financial-affairs-of-someone-who-has-died/