Heating Came On For 1st Time Since February

Everytime I send my meter reading I always get "that seems to low for gas usage are you sure it's correct". Too right it's correct. Cooking and showers only. Determined not to put heating on once this winter.
Our house back garden faces south west, so the conservatory gets the sun (if it’s shining) pretty quickly and once its inner doors are opened it warms the whole house. Saves a bomb on heating I think.