On the IHD I think the second button from the left on the bottom will get you some menus where you will find consumption in kWh.
More experienced members are going to try to help here and the thread will get convoluted. When replying to anything please tap Reply With Quote so we can all be clear what and who you are responding to.
This may turn out to be a combination of things like wrong tariff on IHD, big consuming fridge/freezer, oven leaking some current through the element, immersion heater left on. With patience we will hopefully get there in the end.
I'm an Eon Next dual fuel customer with no particular expertise but have some time on my hands that I am using to try and help out a bit.