Thanks djk for that extremely informative write up. I'm basically going to start from scratch. I've ordered the regs and most of the kit to do the rewiring (a little in advance I think after reading your piece).

I hadn't ordered a master circuit breaker although there is a master switch-fuse (screw in type) after the meter which I was going to leave in. I just need to check if this is double pole as it is not easy to see.
I had ordered a master 100mA RCD (in addition to a 30mA one for the sockets). But sounds like this is not the norm here.

Anyway, thanks again

Robin