Thanks for all the advice

Sounds like I triggered a misty-eyed trip down memory lane for some of
you.

Loath though I am to admit it in a diy group, I think I am going to
have to find an old pro as recommended. The thought of stuffing up the
termination, then blowing the wiring which is cemented into the floor
or plastered into the walls doesn't bear thinking about.

How do I assess the guy (or gal !) is up to the job? This all feels
terribly pricey, but I can't tolerate the RCB tripping every week when
I forget to use only one appliance at a time. Oh the wastefulness of
modern life !

Clive