It has been some time I know, but I was finally able to investigate the electrics on the garage side. It would appear to me that the armoured cabling is NOT earthed there either, the armoured cable terminates in the garage via a small CU type box with two inserted fuses (one for the light circuit in the garage, one for the sockets) and a on/off trip switch (an RCD I assume?).
I don't particularly want to disturb the configuration there but have an idea...halfway down the routing of the cable is some decking, I would like to provide power to that decking area (just two sockets), therefore I could break the cable, install an earth rod, install two waterproofed outdoor-IP rated sockets and therefore provide earth continuity. I am talking at a high-level here, but is that concept acceptable for the earthing to be central rather than biased to one side or the other?
I won't be jumping into doing any of this immediately, but I'd like to know if the concept is viable before we explore the specifics and of course before I start anything.
Appreciate your help.