Marks and Spencer Yellow and Black Geometric/Abstract Midi Dress 3/4 sleeves

Purchased in the UK, label says UK size 8 = US size 4. Beautiful slim fit midi dress with 3/4 sleeves, round neck. Abstract/geometric pattern. Front full length is 40.5". Sleeve length is 19". For reference I'm 5'6" and 150lbs, usually wear US size M or 6.