I noticed with interest the picture of the Ariel and rider having a moment in the mud together .Is the NFS badge on the tank for National Fire Service?
If I'm not mistaken the saddlebags on the Ariel are those made in the US for Indian military motorcycles, and I think Harley also. I had some like that on my 741 Scout. The picture is of a wartime Ariel, with blackout mask, but also with a front numberplate, which might suggest early war years. Could the Indian saddlebags have been readily available so early?
NFS vehicles were painted light grey during the war years and would have had civilian reg numbers. The bike laying down is a SV and has a pre war front guard, so I guess a civilian model VA or something.
The Harley and Indian bags are pretty well the same , from memory there are some differences internally regarding the leather dividers. I doubt we would have seen any of those bags till 1942, but the picture could have been taken anytime after that. Or perhaps they are just some ex cavalry saddle bags?