Bulb - Bills have doubled

Robin9

Can you also post your corrected spreadsheet please. I had assumed that the entries in the gas column had been taken from the meter  and  were m3. On that basis your gas consumption with Bulb is exceedingly low @  2900 kWh.  I do wonder if you are reading the meter correctly or applying a wrong conversion factor (should be 11.2)

Many of these new meters are difficult to read -  look for the decimal point and ignore the figures after it.  A photo of your gas meter would be good,