In article , Andy Wade
writes

Yes, that is allowed. The spur can of course only feed one single or
double socket, or one item of fixed equipment.

Wouldn't that mean the spur would be fed from a 32A MCB (since the OP is
talking about connecting the spur to the same MCB as a ring final
circuit), and thus be incorrect? I'd have said that a spur wired using
2.5mm cable should have a 16A or 20A breaker.