In general when a relative dies, under the trust law of England and Wales it would be the deceased person's personal representatives who would write to a bank in pursuit of collecting the funds of a deceased person for subsequent distribution in accordance with their will or the intestacy rules. For example, if my father dies tomorrow and his bank account contains £1,000, then I would not write to the bank to claim it - I would wait for his trustees or personal representatives to give me whatever I may or may not have been granted expressly in the will or am entitled to under the intestacy rules. This is the only way that a next of kin in England and Wales can obtain a deceased person's assets under UK law. So the short answer is, this question should be irrelevant for anyone living in the UK.
