If you subscribe to the straight forward HC/HP tarif then the periods of cheap rate power will be altered, commencing this autumn.
TEMPO users are not effected.
The reason for this change is to make better use of surplus solar power that, clearly, is at it’s highest during the day.
Consumers will be told at least a month ahead of any change to their contracted hours, & Linky settings will be changed remotely. Not all areas will have the same changes applied.
Long read here…
Seems like a good idea to me. 5 hours at night is certainly amply long enough for the hot water heater, and 3 hours HC during the day would financially enable the use of electric heating instead of the oil fired boiler which would help to reduce the GES emissions.
I am looking forward to being able to run the washing machine etc during the day rather than it waking me up at 3am when it starts its timed programme 
The OH is pleased as he will be able to boost the pool PAC a bit as he likes the pool to be bath like - currently ‘NOT ALLOWED’ as i watch the electricity bills 
I understand that there is some opposition to this change from those with electric vehicles that require more than 5hrs charging per night, and from those with solar panels who sell power to the EDF who may see a reduction in their payments received.
On the other hand, no doubt the change will be welcomed by those that live in apartments with thin walls where running the washer / dryer at night disturbs the neighbours.
It will be interesting to see how it all pans out.