I don’t understand why having the heating on overnight is such a big issue in a student house where more energy intensive appliances might be used such as hair dryers, straighteners, irons and the cooker?
Are you going to insist on all of these appliances are regulated and enforce batch cooking to save money, and insist that all members of the household get a very short haircut cut to save money?
As a student I shared a house that was 50% male and 50% female- we used to cook for longer, wash our bedding and clothes more frequently and use hair appliances, and because we all had long hair, and shaved our armpits and legs we also showered for much longer! I don’t think that the males actually did any ironing either!
Not once did we have any interjections from their parents about this and our wasteful usage of electricity! Not once did they insist we pay more money towards bills.
We had a new combo boiler fitted about 7 years ago and read the instructions about ensuring it was energy efficient, we lowered the temperature of the hot water setting and set up a nest, when we are out of the house the heating goes into eco mode and maintains a lower temperature, as it does during the night when it hasn’t detected any movement but also powers up at 5 am to our ambient temperature ready for when I get up at 6am.
If their boiler doesn’t have a nest, it will also have a timer in it that you can manually set to power down during the night during inactive hours, you can do this with one hour on and one hour off if needed but allow it to warm up gradually for when people get up!
OP I would strongly recommend reading the manual and looking at the settings for hot water before advising your daughter to make demands about the heating being switched off! Also if she makes an issue of this area of energy usage she may find that other energy use by her comes under scrutiny!