Hello and thanks for using Just Answer.
My name is ***** ***** am happy to assist you with your enquiry.
I feel the Bank is just trying to be awkward. Legally, they can ask to see Letters of Aministration if your late husband's net Estate was worth over £5,000. Any Estate valued at under £5,000 is classed as a "small Estate".
On the basis that the pension/life insurances were paid directly to you by way of a letter of wishes, these monies do not form part of his Estate when calculating its value.
Therefore, on the basis that the PPI money was his only "asset" and there would have been a funeral to pay, this would bring the value below £5,000.
I therefore suggest that you write to the Bank and explain that your husband's Estate was a small Estate and that Letters of A was/is not required. They should then forward to you a statutory declaration form to confirm this, and which you would need to sign in front of a Solicitor for a fee of £5.
I hope this assists and answers your question.