I wondered, when you say you have electric heating upstairs if it is on a day and night tarriff Donna? Also I cannot control my immersion at it goes on at 11.30 in the evening and stays on till 7.30am. Unless I physically get up and turn it off. This is so wastefull as there is now only me in the house. I like the idea of a double doored woodburner, what make did you go for?
I do wear layers and find having to wear 3 jumpers all year round is so annoying, in the highlands, we are still getting late frosts!
We had a 7 day timer fitted with up to 3 on/off options per day and the same again for the water heater. I haven't got it on a day/night tariff - we were pursuing one with Scottish Power which didn't come off and I haven't got my act together again to sort one out. I am now waiting to see if we get the farm or not - if we don't then I will look into it again.
Our wood burner is a hunter - which apart from the 'standard size one door options' tend to be made to order - ours has a single glass door on each end. It was £1700

but was worth every penny to be honest. We had a very good local installer put it in. A word of warning though - the necessary chimney liner for a multi-fuel burner is expensive (£70/metre) and we needed 10 metres for a straight run up to the roof. It was something we hadn't budgeted for so it caught us out a bit!
Just a thought - does your immersion plug in, if so you could get one of those plug-in timers. Otherwise wouldn't it be worth getting an electrician to install a timer just for now - I bet it would cover the cost of installation very quickly if your immersion is on overnight.
And I remember well the wearing of many clothes indoors and ice on the inside of windows, even though they were double glazed!!
Donna