Need a new sleeping bag - any words of wisdom?

[KingLooieCatz]

These days we're mostly camping in Scotland and I've been sleeping in thick jogging bottoms, t-shirt, woolly jumper and two hoodies. All at the same time. Woolly hat has featured at times. To be fair the current sleeping bag is about twenty years old.

I'm overwhelmed by the range of sleeping bags available - any words of wisdom?

Mummy bags are the warmest style, rather than rectangular bags (I don’t like a mummy bag, I feel too restricted!). People rave about the silk liners, but I’ve not tried that myself.