My e.on account records my energy use on a month by month basis. April is when I bought an OWL energy meter!
The energy use is generally low for my property as during the summer (mostly) I have solar PV. I have just installed Wind so next year should show a further month by month reduction.
Realistically, All we are doing with the OWL is using it as a reminder to go round switching things off at night. There is more to do, but I expect my consumption to go up again as I am looking at getting an Air Source Heat Pump. Certainly cheaper to run than the oil system I currently have. That, along with triple glazing should mean that next year we are warm!