Tom and Jeroen
Abercrombie built the original Haagsche course. I think it was only 9 holes. The 1924 date probably refers to this course at Clingendael and the formation of the club.
There's a club history at the USGA which I can't read. I'll scan the relevent pages and perhaps you could translate for us Jeroen? From the little I can make out, I think that this course was primarily a CH Alison responsibility.
I just got an email back from Zoute. It simply said that Dunn,Colt and Allen all contributed to the current course. Not very precise, but then not many courses go through 2 ground wars! I'll pester him some more!