northernmonkeyz:[ The bill is totally confusing me.
I can understand that you are confused. I think I see what is going on but unfortunately you are in a bit of a bind.
First of all congratulations on showing evidence of customer readings, that's a good start. I "think" you are on NPower Go Save or other non-standing charge tariff. Unfortunately no longer a competitive tariff and not even competitive with current NPower online tariffs. It features a billing characteristic called "seasonal weighting" and that is the reason why your winter gas bill is so high. To be fair to NPower if you search their website you will find clear information about "seasonal weighting". Unfortunately I do not think it is reasonable for consumers to have to know that first. Note that standing charge tariffs do not feature "seasonal weighting" but usually have discounts deferred for 12 months.
Next time choose a online tariff using a Consumer Focus accredited website (and read and understand the small print). I suspect last time you were bounced by a doorstep or store salesperson. I can't say you have been mis-sold (only because I wasn't there) but the effect is the same.
How to get out of this is difficult to advise. Over a year the "seasonal weighting" will work itself out to 4572 "expensive" primary units so if you leave now you will lose that balancing. On the other hand you are no longer on a competitive tariff.
You need to do some sums using a Consumer Focus accredited website. You (and other reading this) may wish to reflect on a supplier that has subjected you to such an insidious "gotcha".
Post again if you have any questions.