Hi Stephen, and welcome from a bit further south, in Cheshire (although I lived near Preston for a couple of years.)
First, why do you think Jan Zumbach was Swiss?
He was Polish, born in Brodnica, Poland. Having attended the Deblin flying school, he fought with the PAF and after escaping the onslaught of German and Soviet forces, travelling via Bulgaria, he then flew with the Armee de l'Air in France, before escaping to England and flying, originally, with 303 Sqn in the Battle of Britain, before leading the Polish Wing, as a Wing Commander, later in the war.
He also got up to some 'unorthodox' activities, including diamond smuggling, and leading the miniscule Biafran Air Force, before his somewhat mysterious death, in Paris, at the age of 71.
From what I remember of the original mouldings of this kit from 1970, when it was released as a Mk1, the pilot figure is depicted wearing an Irvin jacket, and this would be typical for pilots flying the MkV at altitude at the time 'Johhny' Zumbach was with the Squadron when they had this Mark of Spit.