Terracotta tiles

[Skittlebug]

Are they frost resistant? Are they slippery when wet? Will they survive the harsh British climes?

Yes they are frost proof - make sure you opt for the ones that can be used outdoors.
If you buy from companies like www.ketley-brick.co.uk/ketley-home they offer good slip resistance.
I've specced them on many projects in the UK and they have worn beautifully. I think quarry tiles are gorgeous! x

@BuildingThings thank you! Yes I especially love the look of quarry tiles, it's what I will be going for when I eventually get into the house.