DNO's do not give a toss tbh. I was called out to a job where an "electrician" had rewired a house before the DNO had come to install a new supply. They installed a single phase 2 wire + a 2 pole 60947-3 isolator then put a notice on the head that said NO EARTH.
Said "electrician" came out to connect to the new supply and was confused at the notice and told my letting agent he didn't understand! I got my phonecall from my letting agent about it, I rang DNO to which they said "Don't hold records" FOR A NEW SUPPLY FFS!!
I proceeded to install an earth rod under the hallway floor with 16mm Main Protective Conductor and my Ra was 54.1 ohms.........happy days! Rang LABC about the rewire to see if they would accept a PIR from myself as the "electrician" wasn't in a scam etc, to which building control accepted my offer. Tested the install, bloody DB was wired wrong, ring mains split over both RCD's etc etc.
Anyway, 1 days work, a few phonecalls and a nice payment thank you very much!!