We live in a 1990s built property with no ability to have any sort of open fire (other than a bioethanol fire maybe - does anyone have one of these?), so if we had gas shortages, we'd be entirely reliant on the electricity to heat us, but it would be manageable.
If there were electric shortages we'd have our hideous gas fire to keep the living room warm and the bedroom above it, but no ability to cook. I may buy one of those little camping butane can stoves.
If there are electric power cuts, in a way I hope it is on a cold part of winter, so we can at least keep food, etc cold.
We bought a new fridge freezer in the depths of winter once and instead of making sure I had an empty fridge freezer, I just put everything in cool bags & boxes in the garden (in the actual snow) - it was still frozen when the new one was installed!
As a PP has said, hopefully they'd ration gas and electric sensibly (i.e. ration gas in the day and electric at night). They'll probably rely on people using less if they're asked to, rather than implementing enforced rationing measures.