I moved from Scotland to Finland, so I guess I'm familiar with the UK temperatures ranges!
I'm generally one of those people who is always warm, so with that caveat inmind I don't find -10 to be too difficult. I can travel to the office, or shops and back with jeans, t-shirt a hat and a decent jacket.
It's only when things get colder than -15 or so that I need gloves, a scarf, and more layers. That's the kinda temperature where your face starts to hurt when you're outdoors, and daily life gets unpleasant. You start to think "Maybe I'll go to the shop tomorrow", and plan things so that you don't have to go outdoors like that.