www.citizensadvice.org.uk/relationships/death-and-wills/wills/#h-looking-for-copies-of-a-will-after-someone-dies which has a section “Looking for copies of a will after someone dies”. It also gives details of a commercial organisation that might be able to assist you.
Research shows that many adults (around 50%) have not made a Will, so it may well be that there isn’t a Will.
What happens if there is no Will?
If the deceased did not leave a Will, an ‘administrator’ will deal with the estate. Typically, the deceased’s next of kin will apply for a Grant of Representation (also known as ‘probate’) to be the administrator of the estate.
Where there is no Will (known as ‘intestacy’), the law will decide who inherits the estate.
Applying for a Grant of Representation / Grant of Probate