Our gas bill was £350 for the period 10 Dec to 31 Jan.
1960s detached house, Vaillant Combi boiler (which in the cold weather can't quite get the hot water hot enough for our thermostatic shower, which always mixes in SOME cold, but it's OK for baths if you don't add any cold), 3 bedrooms, 2 occupants. And the house often still feels cold.