I’m using a number of Tado P110 plugs to monitor usage of things like the fridge/freezer, my desk etc. I believe the consumption showing in HA is correct, but when linked through HA using the Octopus integration, its showing crazy energy cost!
Can’t really help you in how to fix it, but I have just this morning started playing around with the same smart plug and looking at mine, I can see the consumption in kWh from the smart plug and the consumption in kWh that the octopus integration is using and it’s out by a factor of 100 for me. Until I figure out how to change it (which I’ll be honest is pretty unlikely) my advice would just be work out in your head that the figures in pence and not pounds as it says.