I'm still quite busy, seeing how much gas I can avoid using, by avoiding the use of the CH. I don't have an actual need to, I'm mainly just curious to see what I can avoid using....
I'm presently working on a night setting of 14C, day of 16C - which seems to only cause the heating to operate once per day, first thing on a morning. I'm supplementing that, with the living room radiant gas fire set on it's minimum, with the hall door closed, just on an evening.
What I find is, as before with the day setting at 18C, providing I have been warm in bed - I always am, then on rising I can remain warm and comfortable for many hours. Likewise, if I take a hot bath, I can remain feeling warm after it for many hours.
I also notice that even though the house temperature is 16C, if the CH has recently fired and the radiators warm - the air feels much warmer.