The bank letter can be a few days before the day you walk at CW no issues there also is are many bank atm and pass ook uodates machines at CW remember to have one transaction that same morning so they see its “ active”
Regarding heirs Only moneys transferred from abroad will be allowed out of the country in case that’s the concern - hence keep copies of the emails received from the bank showing proofs of foreign account transfer - contact a law firm and have a will signed with that specific