Timothy Murphy wrote:

Suppose I add a spur to a power socket?
Or replace a ceiling rose?
Do these count?

If not in kitchen/bathroom you're still allowed to do this type of work,
subject to comptency and regs e.g. the spur must feed direct from the
ring or from an already fused spur.

Or is it just a major rewiring, involving new ring circuits?

Essentially yes.

See the documents from the ODPM website, they're fairly readable ...