I wouldn't agree about struggling to heat your house. Our house has been nice & warm all through the cold snap, & we don't have any other source of heating.
We only moved in mid summer, so we haven't been able to get our wood properly sorted - we were also building up to October so couldn't buy wood in advance even at the start of the autumn (when it is generally cheaper & better).
So far we've spent £540 on wood, and I'm pretty sure now we've got enough wood now to do us through the winter and well into the summer (our hot water is from the rayburn, plus we only have a gas hob, so we'll still be using it for cooking in summer. (I'm pretty sure about quantities, as we had a rayburn in our previous house.)
I reckon just buying seasoned & cut/split wood, it would cost us between £6-700 a year. For comparison, the gas company wanted to set our direct debit at £75 pcm, based on previous bills from the house, so even allowing for the fact that they tend to overestimate, it doesn't seem so bad.
If we buy a load of wood to season, cut etc ourself (hopefully we may be able to store at a friend's farm) we could get enough for 3 years for I would guess around £800 (last winter a load was £700, but I think prices have gone up).
I think what we'll probably do is a halfway house - get some oak slabbing from a local mill (less work to process, & comes in smaller loads, but still relatively cheap), then top up with seasoned wood as necessary.