Be wary of the relying on the government website, councils can and do have provision to override government guidance.
I was about to start work on an integral garage, conversion to home office. All legitimate under permitted development rules. Applied to get building regulations inspector appointment as that's still required even under permitted development.
I then received an email to say permitted development rights had been withdrawn by the council for my area. Not a conservation area, not any TPOs etc, they just removed it.
I am in process of trying to challenge it, as I checked the withdrawn areas and saw nothing.
Ii can apply for a legal letter from the council, to try and protect myself, which would not allow them to challenge it later. If given it removes the councils right to change their mind letter. BUT, they charge a fee of 50% of the basic p,awning application, and still required a le element of elevation plans, materials used, and windows style photos. It's almost the same information needed for full planning application.
I need to get more information off there site, to prove they haven't shown it In a retracted permitted development area.
And yes others have done it over the years.