I used to love Marks and Sparks when I lived in Banbury, Oxon, from from March 1980 to mid year 1982.
I felt very much at home in their clothes, but when I crossed the channel and went to France I felt particularly underdressed.
Over many years I have thought about this, and now think that it is the national body movement under the clothes which define the clothes, rather than the clothes which define the dresser.
Despite the clothes people wear, each nationality seems to have a distinct way of moving which allows a practiced eye to pick a persons origin, even from 300 feet away.