By Free BDM website do you mean BMD? This is restricted to England and Wales, although the non-appearance on the Navy List would suggest he wasn't Scottish or irish either.
I believe that there may be a publication dedicated to Dutch pilots in the FAA, but I don't have it myself. You might like to consider
https://www.defensie.nl/onderwerpen/...ers-raf-en-faa, although I couldn't find a Strit there.