Let's say, for purposes of simplification, that neither GB nor Germany actually get involved, they just support their respective ally.
I believe Belgian deployment was based around the threat of invasion by Germany. There are six infantry divisions and one of cavalry, plus assorted fortress troops and what have you. An infantry division covers Liege, another covers Namur, both supported by second-line troops. In the Great War the Cavalry Division and three more infantry divisions formed up in the Tirlemont-Perwez-Louvain triangle. I'm not sure, but I believe the final infantry division was up at Antwerp, stiffening a load more second-line troops. This is '14 and follows a re-organisation of the Belgian Army a few years before, so this isn't wholly right for a Boer War era fight, but it's the best I can do. I'm not sure what the Dutch had about. I'll go see if I can find out. I recall they had a peacetime (infantry?) division stationed at Breda, but that's all that's coming to mind at the moment.
EDIT: Checked the old
Encyc Brit, which gives no locations, but did give me the number 450,000 for the Dutch Army in '14. By way of comparison, the Belgians mobilised 177,000 for WWI initially, of whom 35% were fortress troops, and 267,000 in total (
The WWI Databook). One presumes they could've managed more if the country were unoccupied, but I'd not care to be the Belgian general tasked with devising a plan to defeat the Dutch!