Unique fitted jacket with Chinoiserie details

Bought in Covent Garden, London, UK. Not really sure what to call this item: Chinoiserie jacket? Not quite a blazer or a blouse. Anyway, you could style it a number of ways: I wore it over a black strapless dress at a wedding but also wore it with jeans and a tank top. Amazing pin-tuck details, bell sleeves and knotted fastener. A search of the brand comes up empty so ‘size 3’ is meaningless. Listed as medium: PLEASE look at the measurement photos and ask me for more size info to be certain.