I have a spare quilt/duvet I am using in an evening whilst watching TV. I have recently had an hole in the wall electric fire which I use the flame only effect to mimic a bit of warmth and only turn the heating on low if the weather gets really cold like it did over the weekend. In the day I use a thick dressing gown if needed.
I could weather the 54% increase, but acting cautiously now as the October price cap might be another storey.