many people have and frankly I kind of envy you. My Dad instructed a solicitor as well as me and she refused to stand down and let me be sole executor, so she'll be trousering some large fees for a job i could have done myself. I did my mum's, in England it was a bit slow but very doable. She did not hit the IHT threshold. I know Scottish law is often different but there are plenty of resources online to guide you.Hopefully someone with experience of going through the process in Scotland will be around here soon.
You are welcome, I am a great believer in the lay person being able to do a lot of jobs it is assumed require a solicitor. If you take it one step at a time and get help eg form websites/ citizen's advice/ helplines (in England there's a probate helpline) it should be OK. Make sure to keep full and clear records as you go along. I always use a dedicated notebook whenever i embark on a big bureaucratic task.
I did my DDad's - it was fairly simple, bank accounts, investment accounts, a few shares and property, under IHT levels and everything left to Mum. Our sheriff's office were actually quite helpful - took the first draft in and they had a look at it and tweaked a few things. The thing I did have to change was the list of assets - it needs to be fairly detailed with account numbers, institution, investment name etc. And being the Scottish legal system some of the wording you have to use is a bit archaic!
There are a few online resources but I found citizen's advice absolutely useless. When we submitted the completed paperwork to the local sheriff's office, it was finalised very quickly.