I came across such an install a few years ago. The previous owner had long gone, so nobody to question. With the rod disconnect I had a suitable test result for the Ze.
I was concerned though, that perhaps the earthing facility had proved unstable previously. So I contacted the DNO, who sent out an engineer. He said there was no history in the area for earthing problems, conducted his own tests, and I enquired about changing to PME system.
We then went into an unusual discussion, as (he said) the application would take some time, and that the supply at some point between this particular supply and elsewhere, had probably been repaired and changed to PME anyway, so why not do it yourself!
Anyway, after asking advice from my Scheme, I removed the connection to the earth rod, and left it as TNS, with a note & pics on the EIC.
