I have a 1950's Met No 1 uniform and the duty arm band is held in place by two thin pieces of serge through which the arm band is threaded. Was this the normal method on all uniforms of the period or just unique to the No 1 uniform? I also have a reproduction uniform based on the 1930's - 1940's but nothing to secure the arm band. It seems that it would have been a constant issue repositioning the band with nothing holding it in place