hello Koen,
Unfortunately, I have never found a pic nor profile of the real plane of Jean de Selys Longchamps, despite hours of research around the internet and a lot of books.
I've got the serial number and code of that specific plane with the huge kindness of poeple from the "Musee Royal de l'Armée et d'Histoire Militaire".
I found pics from differents plane of the 609 sq but noone of the plane Jean de Selys Longchamps used on 1/20/43 for the unauthorized raid again the bld Louise's gestapo office.
Fortunately british planes had standard camos and markings so it's not a too great gues