the main part of the house was rebuilt 2016, the dual supply is because there is a small annex attached to the house which was separate; but is now part of the house.
i had the new air source joined to the small annexe meter, which had hardly anything on it before, tiny bills. now that bill is £300, for january, which makes sense as it is powering all the heating and hot water and it has been cold.
but the other bill, which should JUST be powering my lights (90% LED), kettle, toaster, oven etc is £1900 for a month. this doesn't include any heating hot water etc.