We hadn’t realised quite how efficient our house is, being new to oil. 4 bed , water based underfloor heating with radiators upstairs uses one 1300L tank per year. We have solar panels which also help to heat the water.
Nannytopsy - your solar panels must heat the water efficiently to only use 1300 ltr pa. We will be pleased if we get through the year buying 1800 and this is a smaller house than yours ie 3b. Electric fire/oven and hob and our electric is anticipated to rise by £200 pa.