Aussie, as far as I know we were manufacturing plugs first and then sockets later. What I would like to know is; were BS type sockets ever used in Australia/NZ ? And where did our 3-flat-radial-pin plugs come from ?

Can any old Antipodeans help here ?

I think the "Figure Eight Flex" you're refering to is our TRU-RIP ( brand name ).

The three-core Tru-rip here is double insulated with coloured core insulation and a white plastic sheath.

Tru-rip has been superceded by flex and is not really used much any more.