Stylish, smart but warm jacket for weekend away

[Floopbloop]

Does it exist? In a size 18?

No idea what I'm looking for at all.

Going on a girls weekend away to Edinburgh soon and ideally I'd like to only take one jacket that will see me through the train journey and sightseeing and shopping, but also be nice enough to wear to go out to dinner, cocktails and bars.

No budget in mind as yet, but I'm more high street than designer.

What kind of thing would you wear?

There are sales on every where. What colour do you like?

I know peachy, hopefully I will get a sale bargain, just no idea what to look for! I only really wear practical waterproof type coats or denim jacket in summer.
I don't suit pastels, bolder colours or dark neutrals are fine. I'd be open to something bright or grey, navy or black.

What about a navy wool pea coat? Warm enough for daytime and fairly smart for evening too.

(Pack a thermal t to wear under your day clothes as Edinburgh is typically very cold!)