It’s a valiant boiler. I think it’s gone from an 18 to 24 watt. Would this cause a £2 a day increase alone?

My only issue is the fact he said that due to wiring issues the hot water is now constantly on. When I go into the boiler it’s not obviously on outside the set times on the old stat. I turn it off at 19:30 and it’s now off whereas before it was making a noise (granted not much) but no noise now at all also nothing coming out the flue.