Have a look at this, cupotee.
Economy 7/Domestic economy meters
This type of meter gives you seven hours of cheaper electricity during the night.
It has two readings – a ‘day/normal’ reading and a 'night/low' reading.
The timings for the readings depend on where you live and the time of year. Get in touch with us if you'd like to check what the timings are for your meter.
Just so you know, the clocks on Economy 7 meters don't change for British Summer Time (BST). They stay on GMT all year round.
https://sse.co.uk/help/energy/meters/types-of-meter