Seems there could be a bad connection in a joint or where the ECC cable was terminated.

Lucky the lead cable is not the issue in this case.

100 m of 10 mil was used to link the earth terminals in the meter rooms and a reading taken at the main switch of a DB indicated 0.6 ohms.

It looks like the easiest solution will be to install a new separate earth cable from meter room to meter room.

The joke is the all the COCs which have been issued. I suppose you could turn around and say at the time of test the reading was any number you make up within the standard. It would be your word against whoever challenges you.

Another reason why ever COC should be recorded using a gps.

Until this happens or some policing and some real punishment is imposed, COCs will continue to be a money making for anyone willing to take a chance. Maybe i should start issuing COC as Jack Sparrow again. To think i got away with it for years because i was a pirate contractor. It is a f$&@ joke 😏