Luis, your first photograph alongside the Austin K5 G/S Air Portable (I've never seen a photo of one of those before, so thank you :-) ) seems to have been in service with the Belgian 1031 General Transport Company as part of 21st Army Group.
This suggests that RASC GT companies might be possible users of the W/NG. It was certainly so that the faster OHV machines were thought more necessary for convoy outriding as they were constantly overtaking.
Luis your first picture today is a Canadian bike. They had a habit of adding mirrors and lights well before the Mods of the 60's thought they had invented it. I suspect it was for celebration and parade purposes. But they had an even stranger habit of riding on a piece of Sorbo rubber strapped to the tank top which you can also see in that picture. This guy on a Norton illustrates the weird behavior. I've got another picture somewhere of a Canadian riding on the tank top during a victory parade with two girls sat on the two proper saddles??? One way of pulling the birds I suppose. Ron
Here's another guy riding on his tank. I expect it was their way of adopting the Harley riding position, and I've read that it was not condoned by the authorities. In fact it was actively discouraged. But who was going to accost a signalman delivering urgent messages. Ron
Delighted to see one of the machines displaying an RAF roundel on the tank. Not many photos of the W/NG with the steel mag chain cover as opposed to the alloy cover but several more seem to have the all steel primary chaincase covers as opposed to the alloy and steel covers.
As I mentioned on the FB post, the blanking plate over the unusued rear lamp aperture suggests an undelivered French contract machine. The earlier photo of a French bike clearly shows an opening on the left of the number plate....the off-side in France.
That last picture is interesting, the "40" serial on the tank seems to be on a roundish shaped Signals? backing, could it be an Anti Aircraft Command machine, its said they used an ellipse shaped serial.