highcontrast: Still think that 150 pound bill for a month of gas usage is high to much. I just have no clue how to dispute my bill.
Your "102" (100s of) cubic feet from 1/11 to 2/12 is consistent with your 4390kWhr for the following month. While potentially "excessive" it is within the bounds for a central heating boiler running 24/7 in the severe winter conditions just experienced.
So the question is what type of heating do you have, have you been running it 24/7 and how well (or badly) is the flat insulated?
Since you are taking actual meter readings (from an imperial meter) *probably* the bill is correctly calculated. (Important: I take it you checked the meter dial says ft^3, not just the bill?).
If you believe the meter to be inaccurate you are entitled to insist the meter is tested for which you are liable to pay a statutory fee. Be aware that gross meter error is very rare and other explanations should always be looked for first. You should first consider the answer to the heating question and get a handle on your consumption by taking daily readings.