Sizing on Lululemon Rain Revel jacket?

[melonhead]

I'm eyeing up the Lululemon Rain Rebel jacket but I can't work out the best size for me and it's too speedy to take a punt

Has anyone got it? I'm a busty (36E) size 14 (5ft 7) and am always a 14 in shops like M&S, Next, FatFace etc. So I don't know where to go for the US 10 or the US 12?

I don't want to be swamped or to wear massive jumpers underneath, but I do want to be able to layer a vest and a merino jumper.

Tell me what to buy?!?!

Spendy, not speedy ffs

Yes I know the one. This jacket runs small - especially on the shoulders and the bust. I would definitely say US12 for this specific jacket if you typically wear a UK14.
(I know online returns are a faff and better avoided but they do offer free returns if it’s not right after all).