From the Octopus Smart Tariff group Martin Shoebridge posted a link to this rather groovy app:
You really need to use the hamburger menu (top right) to explore all the things it can do.
It’s helped me work out the penalty I’m paying for not being on Agile. We’ve agreed as a family that we’re willing to pay that penalty for a simpler life. I actually moved off Agile and shut down a bunch of my robots.