Andy,
Most of their findings can be found back on the website of the Netherlands Institute of Military History (or rather its name in Dutch):
http://www.nimh.nl/nl/
Once on this website, click on "Collecties" and when opened on "Documentatie".
Then you'll see in the text "Verliesregister 1939-1945", with clickable years just below it.
These contain pdf-files with the air losses in the Netherlands as were known on 1-1-2008 by the Study Group.
Full link should be this:
http://www.nimh.nl/nl/collecties/Documentatie/
Good luck!
Leendert