Live by myself, house is rated C/C. IPR light throughout most of the house, very well insulated. Thermostat set to 18c in evening, house is usually 21/22c.
My house is rated C/D and the second rating is your carbon footprint so doesn't really matter in terms of how much energy you use.
I've since installed solar panels so my rating will have improved slightly. I could do with a new boiler at some point as mine is around 25 years old. No point replacing it until it dies.
I've installed led lights in every socket available. I have in most cases got the best energy rated products.
The size of the house and location is important. Up here in Scotland I will have my heating on most of the year bar maybe 4 months. It's a large 3 bed detached. For example the house next door is also 3 bed detached but much smaller.
If you live nearer the equator the less heating you require. Still though £35 a month I reckon I use that alone in electricity never mind gas on top which is far more.
Essentially it can be deduced you live in a rather small place nearer the equator than I do. Even if I turned my heating off completely. I'd still be likley paying more than you. Unless it's summer and my solar panels are doing their job.
Regardless the amount you pay isn't really what we want to know. It's the tariff.
How much you pay per day in standing charges for gas and then electric.
Then how much you pay per unit of gas and then electric.
That's the important part. Because I cannot turn anything off. I use what I use and that's why I cannot reduce my bill without spending thousands on a new boiler or triple glazing, etc. All of which would only reduce it a tiny amount so pointless doing until they fail.
