Mhmm so to unravel that a bit, you
@the pict find your Zs lower than Ze. It has been mooted (correctly in my understanding) that paralell paths on actual Zs may account for Zs being lower than Ze. The DNO came and tightened a PME connection at the cut-out. You say this was the reason you had lower Zs than Ze. I am a bit confused as I would have thought you would have a variable reading if the connection of earth to the PME terminal was poor? But is it really the answer, what did your subsequent test reveal, you left me hanging a bit with your statement.