I did it for my late DM. But she was very organised, having had to deal with it for her mother, aunt, and grandmother herself.
I had a notebook and pen, a box file, and a bunch of cascading Todo lists in the Google Keep app. Everything I did or received - calls, visits, letters sent, forms filled in, monies paid out or in - went in the notebook.
I didn't get solicitors to do it for me, BUT I did pay them for advice on what the will meant exactly in some places and what actions they recommended I take, plus, sorting out the Land Registry forms which were less obvious because of a will trust.
In the course of events I may have to do it again 3 or 4 times. The trouble is that the scut work (gathering up all the accounts etc) you end up doing anyway!
I was a professional problem investigator (for a very niche area of software) and approached this in the same deliberate way : what do I know already, what do I need to find out, and what actions are required based on what I know right now? So I would have a main todo list with, say
"3. Sort house"
on it, then a "House" to-do list which would start with "Find out what to do about house" and then have more items added as I did so.
Friends who had been through it already were happy to give me tips.
Ironically the organisation with the most traditional procedures - Newbury Building Society, who got me to make an appointment and turn up with various specific documents - were the easiest. One and done. Halifax were happy to do stuff online or on the phone but screwed things up repeatedly.