Of course the quality of the insulation in your house will make a difference to the heat loss overnight, so even if everyone's heating went off at 10.00pm, there would be an enormous variation in the internal temperature of the bedrooms at 2.00am, depending on the level of insulation.
Our house is 500 years old, we do have as much insulation as recommended in the loft but cannot replace the single glazed windows with double glazing and our solid walls are quite thin in places, although we have some internal wall insulation in the bedrooms