The message
from Guy King contains these words:

But they /are/ protected by a 13a (or lower) fuse. Several sockets
loaded to
3kw on a spur with 2.5mm wiring will overload the fixed wiring.

Shouldn't do - that's what the 32A breaker in the fusebox is for!

But the spur is in effect a radial circuit and radials in 2.5mm have 20A MCBs.

--
Roger Chapman