On Sunday, 17 March 2019 16:00:39 UTC, Graham. wrote:
The other one is "Kitchen ring circuits must be exclusive to the
kitchen". Has that *ever* been the case?

Not AFAIK, and there would be good reason for a kitchen sharing a ring or rings with other rooms with low power demand. A lot of houses are split front/back with means the kitchen shares the socket circuit with the back bedroom.

I grant you if you were rewiring the house, you would almost certainly
design it that way, but is there really a hard & fast rule about it?

No, and really rather inconvenient if *all* the sockets in the kitchen went off. I'd much rather split a kitchen over two circuits if possible.

Finally, I have run into the same issue with this electrician as last
time, which was partly the reason I didn't go ahead with the project
last time, basically, he wants to put as separate radial circuit for
the new hob or cooker as he does not want to use the existing 6mm 32A
circuit for both.

Ask to see his demand and cable sizing calculations as part of the design certificate.

Owain