Oswald Mosley based his uniform on a black version of the sporting dress for fencing. I don't think any other fascist or other paramilitary organisation for that matter wore the same shirt as the British Blackshirts.
The Irish Blueshirts would be another interesting set of figures and the shirt, tie and beret could probably be used for other paramilitary groups of the 30s.
I am not averse to marching figures it seems that apart from the earliest Airfix sets most figures are in fighting poses. Angry civilians c 1930 -1950 would be good for lots of situations and would give a bit more substance and background to my Hungary 1956* figures.
*latest recruits are the Zvezda Soviet Militia- the woman in this set is like a well known photo of a young Hungarian revolutionary woman