Richard, thanks for the heads up on Furse.. Quite some time back I was required to attend a then new tracking station on South Uist built on the top of a mountain. Apparently the elect engnr told me it cost more to earth than wire the building. I was told they had to dig up the peat bog at the bottom of the mountain, lay down acres of copper mat, and lay the peat back down on top..?
My house sits on mostly rock with perhaps a meter of soil in places, thus earth rods don`t cut it.. When I built the most recent extension I used plastic for the water pipe, part of the mains supply it plastic too, dug down and found the old out of use 2" steel water supply pipe, cleaned it up up and connected to that in order to get some sort of earth reading and to pass the electrical safety test regs for my then new self-build.
Prior to that I used to get an occasional tingle from the conduit mounted metal light switch in the garage, when the paint wore off the switch, any time I was spraying paint I would give the old switch another coating of paint... Yeah that garage is long gone, saved me rewiring the place, I built another home extension over it`s foundations..Madness...Duh !!!