Cost of central heating (UK)

[polka6]

Please can somebody wiser clarify a couple of points for me:

1. Does it cost the same to have 1 radiator on vs several/all radiators? Is it the same hot water pumping round and wouldnt make much of difference if its one or many ?
2. I presume the higher the temperature, the more it costs. Is it cheaper to have for eg. central heating on to a set temp like 18degrees 24/7 or cheaper to turn it off over night but have it much warmer, perhaps 20degrees all day but turned off at night or even 22degrees for a couple hours in the morning and a couple hours in the evening.

Thanks!

It would be more expensive to have more radiators on

On your second point, there is a lot of debate about this and the answer really comes down to individual houses and insulation. If you are in a Poorly insulated house it would likely be more expensive to always have the heating on, whereas if your house is warm and keeps heat it won't be so expensive to do so. But ultimately, the longer you have the heating on, the more expensive it will be.

As above. We usually give it short blasts to warm the rooms we’re using to 18 degrees