A reader had recommended Luc Eekhout's book
Het Admiralenboek: De vlagofficieren van de Nederlandse marine 1382-1991. The copy that arrived yesterday is one I ordered directly from the publisher
BV Uitgeverij De Bataafsche Leeuw. I had ordered by email and they sent the book and invoice. I'm hoping that I might make use of the book in my research. If nothing else, there is blogging material on the admirals.