Electric Shower, Gas Heating 1
If you pay for gas and electricity but your bath or shower has a device similar to figure 1 then you have a electric shower that draws on a cold water supply and heats the water on demand.
Immersion Hot water, Gas Heating 2
If you have a device that looks like this in the property and there is a device bolted to the top or the side of the tank (much like the grey device in the illustration), then your hot water stored in a tank and kept hot by an electric filament
Gas Hot Water & Heating
If you can’t find a hot water tank, and you don’t have an electric shower unit as described above, then your hot water and central heating likely use gas only.
If you only pay for electricity and you can see no evidence of a boiler or any gas device then the property is only supplied with electricity.