In the UK, there is no requirement for a will to be registered anywhere, and it does not have to be drawn up by a legal practitioner. The deceased might have downloaded a form from the Internet, filled it in as best they could, then stuffed it in a drawer. Many people also do not have a will at all.
If there is a will, then it ought to name an "executor" (someone who can take charge of the deceased's affairs according to their wishes), who ideally would be someone who is still alive and willing to do it. If those conditions fail then an estate administrator can be appointed, and if there's no will then the administrator must follow the default rules for "intestacy". Often, the executor is someone within the circle of the deceased's family and friends who would find out about the death fairly quickly, and is already armed with some knowledge about where to find the will itself. People may also choose their bank (who would also soon be in the loop in the event of death) or their solicitor, either of whom might be looking after the original will.
If the will and executor do not emerge organically as news spreads, then someone will have to take responsibility for finding the deceased's will, or confirming that they don't have one. Helpful hints will include -
- remembering things the deceased said during their lifetime, such as "my will is in the shoebox in the spare room wardrobe" or "I've named cousin Alfred as my executor" or "Flybynight LLP was really helpful"
- going through their papers to find a will, a solicitor's invoice, or anything like that
- calling around local legal firms to see if any of them have acted for the deceased
- searching the "National Will Register" in case the will happens to be there (despite what the name might suggest, registration there is entirely optional).
It often happens that firms close down, change names, are bought by others, etc., and so the relevant solicitors may be completely different from the ones who were involved in originally writing the will. Practice rules mean that the documents still ought to be retained, but many things can happen over a long period of time.
There is no automatic system for notifying others in the event of a death. The government in Great Britain operates a scheme called "Tell Us Once" for updating all government departments, but the private sector does not hook in to this. Sometimes, people place notices in the Gazette: see the category "missing wills", as well as "next of kin" for finding relatives of the deceased. (The reason for this is that notices of probate are also placed in the Gazette, to identify creditors of the deceased who might have a claim on the estate, and so relevant parties nationwide could have their eyes on the Gazette already.)
Something else to note is that when following the practices above, there may be several wills found, as well as "codicils" (which are amendments to wills), and any documents found might not actually be valid. Perhaps the form downloaded from the Internet did not get witnessed before it was stuffed in a drawer. It can be a bit of work to identify the last valid will.
The reader may well feel that the situation described above is not optimal...