We're on the old THTC system that was put in throughout the Highlands years ago. It stands for Total Heating with Total Control, we have two separate electricity meters on two separate rates, one has all the storage heaters/panel heaters on it and the other has everything else. I can turn the heating on or off at the wall and set the storage heaters to boost us in the morning or the evening, but other than that, SSE has control of that circuit and they choose when power is supplied to it depending on the forecast for our area. We get between 5 and 12 hours a day of power to it. The other circuit is unrestricted, but it's charged at a higher rate than their standard rate, while the heating circuit is supposed to be at a very low rate, but it was 7.65p/kwh when we first moved here 13 years ago and is now up to 16.73p/kwh for the heating circuit, 20.6p/kwh for the other circuit and 27.49p per day for the standing charge.
Until recently it was impossible to switch away from without getting your circuits rewired because no other company would touch the two meter system, but they've recently managed to overcome that, so I can have a look at switching - but they're ending support for these meters soon and will be swapping everyone over to a single meter system, so I might as well hold on and get them to do the work (plus we're hoping to do a lot of work on our house early next year, including getting an air source heat pump and full central heating fitted), although goodness knows what they'll switch me to, as I'm in an area where smart meters don't work (no signal). The meter at my holiday cottage down the road is an old key meter I've been trying to get swapped out for three years, it broke over Christmas and I'm now getting free electricity there while they try and figure out what to do. They do have a small stock of old meters, but their protocols say I can't have one of those unless the power goes off and five months later, the power still hasn't gone off! According to a friendly SSE engineer I spoke to, I've done my bit in informing them of the problem in the first place and all they can legally bill me for is the daily standing charge when they finally sort it out.
Sorry, off-topic rant about ancient Highland heating systems over...
I was quite perplexed by your charging structure, but fortunately found this great gif which explained it all. (@Harrybosch )