Hello
Reputedly Bader was downed by Buck Casson somewhere near St Omer in the summer of 1941, and I think two other Spitfires likely went down to friendly fire that day. Identification was a big problem, though obviously it was not discussed in public.
In regard of Milicer, yes, I have heard of him, and I recall an interview with him published in 1980s in a Polish aviation journal. As I recall he claimed that the aircraft was finished by unfair competition from Cessna, which offered dumping prices, and lack of the reaction of the Australian government, which did not introduce import taxes. I do not remember if he suggested corruption or not.