After serious thinking wrote :
Spain is not often noted for leading the way but their new pricing for
electricity, which has three price periods per 24 hrs, and includes weekends,
seems better than the UK's E7 system.

This along with proposed surge pricing (for periods of high demand which
could have had user agreed load shedding) was the great opportunity that the
UK government managed to waste with the superfluous (and entirely passive)
smart meters.

Hardly a missed opportunity, Octopus optionally offer a tarriff which
is entirely variable, they just advise you in advance what the rate
will be. Nothing to prevent other suppliers doing similar.