Here a modern consumer unit always has a 63Amp Neozed fuse and a main isolating switch on board.

Pre-meter is

60/80/100amp sealed black unit.

3phase isn't really used very often domestically although in small commercial it's fairly common. cookers / showers just take a 35amp single phase 220V circuit on heavy cable. Water heaters usually take 20 Amp. I've seen plenty of 3phase water heaters in France.

A lot of cookers ship to here with the possibility of hooking them up to 3phase though. 220/380 (230/400)

The standard UK cooker control (with socket outlet) is outlawed here for some reason. Any explanation?
They used to be quite common in the 1960s and 70s. All that's allowed now is a large flush fitting dual pole switch on the wall. Sockets have to be on socket circuits.

What was the point of that connector in the uk?