I mentioned these to John Meadows a little while back, they appear to be from an all two-stroke "Motor Cycling" event at Silverstone to celebrate Villiers' 60th year, reported in Motor Cycling Jan 8th 1959. Unless John has discovered otherwise, this appears to be the event where the Frisky crashed. It's given a four page article with several scooters, motorcycles and three-wheelers discussed and portrayed, but no Frisky photos, and very little mention in the text other than -
"Two more three-wheelers, a Wolverhampton Frisky and a Yorkshire made Scootacar, accentuated yet again the ubiquity of the 200cc engine in modern fan-cooled form. A transmission fault put the Frisky out of the running, but not before it's works driver, R. Kerr, had established that driven hard, this newcomer to the three-wheeler class will average 57mpg."
I'm guessing the transmission fault upset the slightly driver more than the journalist.