Spending £2300 a year on electricity

squawkbox

To the OP, you have to be careful. As everyone has highlighted, the billing so far has been estimated. There might even be a chance that the usage is higher than the estimates... this might put you in a difficult place. (i.e. it might given rise to "if you hadn't started poking around..." type comments).

collectors

Have a look & see if you can have an online account with your supplier so you can get all the details online. You should be able to go back through the bills & print them out.
With that size bill I would think about something like an Owl electric monitor assuming the house has broadband, so you can keep an eye on usage.
I get these detail from owl & the online part is free. Admittedly the one below is a three-phase one, but the normal single phase one is very similar.