As our existing fixed energy tariff with EON was coming to an end, we've opted to switch to another fixed one from the same company called "Next Smart Saver Fixed 12m V38" (however do they think up these snappy names?). This comes with a higher peak electricity rate for 1600-1900 and a super off-peak rate at night. I estimate that we might make a small saving overall as we rarely do much cooking before 1900.
Adopting this new tariff requires us to have a smart meter, which we do, and to having its readings taken every 30 minutes - I thought they already were but apparently not. We have a display unit in our kitchen which shows the electricity consumption in W/kW updated every 10 seconds, which I occasionally glance at and find useful. This has never worked for gas, for reasons unknown.
Remarkably, EON also says that after switching to the new tariff our home display unit will stop working. I simply can't imagine why. Since nearly everything else that energy companies say about smart meters is false, this might be too. We'll find out in a week or so.