Sorry to be late in on this, and I don't know how accurate what I am going to say reflects the position throughout the rest of the UK, but as I worked until recently in a GP practice in Scotland for 25 years, ( I retired 31/12/2020), I am well aware that the paper records for a deceased patient were transferred back to CSA (Common Services Agency), shortly after their death, and similarly the online record was 'transferred out', back to CSA, when patients either left or died. In the case of traditional/historical paper records, these records were only held on to (by CSA), for 3 years, and then destroyed. I would assume that the same would be likely for the online/electronic record too.
Paper record making within the practice ( ie clinical notes), stopped in my practice at the millenium (being replaced by entry into the online record for the patient), while incoming letters were scanned to the electronic patient record, starting in 2004. Initially the letters were still filed in the patient record, but from about 2009 the original letters were shredded once a confirmed system backup had been verified. In the same way, the vast majority of paper based letters to the hospital, etc. disappeared, being relaced by electronic transfer more than a decade ago.
I hope this 'wee' summary might be useful and informative. I don't know what happens at the hospital end, but I am sure they would have very similar procedures! Certainly, the vast majority of mail to the practice from secondary care (ie the hospital sector), has come in electronically for a number of years!
Jane
My point being that records may not be available for deceased patients for very long!