[Franek Grabowski]

Gerry, there was a discussion about Tuck, his family denying any Jewish links.
Concerning Polish airmen, it seems major source seems the work of Benjamin Maiertchak listing all the fallen Polish soldiers of Jewish descent. The problem is that plenty of the names cannot be confirmed.
Of the airmen listed I have contacted family of Zygmunt Klein, and they clearly denied any Jewish links, the man being RC himself. A friend approached family of Marceli Neyder, also listed Jewish (albeit for some reason not by Sugarman), and the reply was exactly the same.
Another airman, Franciszek Jastrzebski, is listed as possibly Jewish due to his name, but it is perfectly Polish.
I cannot comment on Jan Piotr Pfeiffer, but I have found no positive proof, and I have a list of over 100 Polish airmen of Jewish faith.
Mentioned in the article Ryszard Bychowski, Zygmunt Glass, Rubin Lipszyc and Eljasz Posner indeed were Jewish but as they have served in bomber squadrons, they do not qualify for a BoB list. This is also the issue with many of the Britons listed! That said, it is intriguing, why he did not bother to list German airmen of Jewish origin, that would make a nice comparison.