Got an email from Mr. Gramser here in holland, and he says al Dutch bikes can be easily recognized by the little reflector on the front of the front mudguard, so it's present at the above picture, hence Ex Dutch contract!
The Dutch were taking substantial quantities of KM21s as far back as January 1939 - I don't have any copies from the JM ledgers.
It's difficult to be precise as the War Office deliveries may have had separate blocks of numbers but the impression is that they were taking more than the British at this stage.
This could be because the Ministry of Supply still thought that Nortons could supply enough of the preferred machines.