Martin Bonner wrote:

But does the change mean that somebody out in the sticks who finds
that their supply often drops to 220V will be stuck with it, but in
days of yore the Electricity Board would have had to fix it somehow?

Yes, but bear in mind that that the minimum voltage (216 V) should be
maintained up to the full current rating of the supply, generally 60 or
100 A. If the voltage drops below 216 when you apply a heavy load then
complain (and complain, and complain...).

--
Andy