End of the Royal Signals

I have not found solid evidence that the Royal Signals (or White Helmets) ever rode on Royal Enfields, the closest I got was this picture,

which seems to look like WD/L's with Burman gearboxes, but many bikes of the time looked alike. What is clear is that they were the inspiration for the Daredevils, who most definitely do.

Now they are coming to an end. The alleged reason is that they are too "old fashioned", but the kinds of crowds they attracted casts some doubts on the motivations...