Ian and Tony,
Have done a lot of research on these, and years ago looked into a WW2 parts list, and no 26" wheels were mentioned, and have watched the big sell out of these from the Belgium Army in the 80's and never seen 26" wheels on them, later in the 90's all these glossy green Phillips ones were for sale at Beltring, for very little money, and did buy 2 at the time for spares.
So as to the the above link, of the 1939 one, if you look closely, the same deep bronze green is under the matte paint, and for me that is also a postwar indication.
But I could well be wrong, and if anyone finds some conclusive proof, I stand to be corrected.
Just found on another forum, a post by Johan Willeart (of H-D fame) that only MKVI bicycles had 26" wheels, will ask him about it.
Here my 1946 V.A.O.S. that does mention the 26"wheels and tyres;
Here my spares chest, clearly postwar, and carries 26"spare tubes;
I won't bore you with too many pictures, but here some WW2 b/w ones, all big wheels;
As you all probably know, only the rear carriers were dated, and no lists of framenumbers with contract dates exist, but a friend is looking in the N.A. so who knows what might turn up?
Cheers,
Lex