From November to end Dec you used about 1200kWh, that is almost my annual total. It is your electric heaters causing this. Storage heaters heat up at night and blow out warm air in the day. Maybe your two heaters are heating up every night and you do not use the heat. You must definitely completely unplug and isolate one of the heaters, Also you could ask SP to transfer you to an Economy 7 tariff, this gives cheap night electricity. Your meter may need to be changed and you should ask your landlord about changing. It would be cheaper for you now to isolate both the heaters and buy an ordinary fan heater in a shop and only use it when you need it.