We were running spurs from the ring main and adding new outlets which is definitely not allowed without inspection now.
It’s really not that complicated and I’d feel completely comfortable doing it myself today but I understand how that may not be true for everyone so the requirement is probably reasonable.
Spurs have been re-legalised: the Part P changes have now been rolled back to whole new circuits, and spurs and new outlets are back as non-notifiable along with new faceplates etc.
That said, you're theoretically supposed to do a full set of earth resistance measurements etc. on the new wiring, which is hard if not impossible unless you've got proper electrician's test equipment. But in reality no one does that when DIYing it.