The biggest consumer of energy in the home are what we call "Current Vampires", these devices consume electricity even when off.
things like the cell phone charger, even when the phone is not plugged into it, it will be consuming energy, not very much but it adds up, other things like the stereo system, the HDTV or anything that uses a remote to turn it on uses some amount of energy when off.
Anything with a switch on it that has pilot light in it will consume a tiny bit of electricity, when you turn your computer off do you also turn the external speakers off?? (if you have some)
If you are worried about the electric bill, and want to see what is costing you so much, then get one of these hummers,
Kill A Watt Meter - Electricity Usage Monitor | P3
They have others for the UK here,
https://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias=diy&field-keywords=kill+a+watt+meter
Get one, test your stuff, add it up and see how much these current vampires are costing you each month.
Most of the stuff I don't need to be on all the time (stuff with remotes) I have on a switch.