EUC Navy linen-like jacket from England, US size 8

I bought this jacket in London from a store called Next but only wore it once for a couple hours. The tag says size 12 but that’s for the UK. It’s US size 8. The back flap is still sewn closed as are the two front pockets. This is a nice all season jacket with a little bit of stretch. The gold buttons are decorative with no button holes. This is a really nice jacket. But it was a desperation buy because I was cold and it’s a little too big for me. Measurements are: 20” armpit to armpit, 28.5” from neck seam to back hem, 25” arm.