To those electrical experts out there.....how would you respond to this:

"we should label all the circuits on every distribution board"

Response: "there's no need. it's too expensive tracing all the wires and if there is a problem that requires a circuit isolating you can switch the main panel breaker"

I know it is a requirement in the IEE regs, but from a basic safety standpoint, what risk is there that could not be overcome from flicking the main breaker panel??

your thoughts and responses are very welcome

hopefully not seen as being pedantic, but a switch is not an isolator. Each circuit should be capable of proper lock-out isolation for the obvious reasons described above.
Labelling is very good practice and a useful aid, however SSoW will also properly test that circuit to ensure the one we think we have isolated is the one that is actually dead before we go poking body parts near it.
Routine Test and Inspection by a competent electrician will list as a non-conformance any circuits not identified at mains and sub panels.