William,
Both individuals are astride 3-1/2hp Sports models (circa 1922). The inlet manifolds appear to be non-standard, though it looks a similar arrangement to that used on Cyril Pullin's 100mph record setting Sports machine. The rear carrier also looks non-standard, but again more like the 100mph record setting machine, rather than the pannier toolboxes seen on the catalog model. No road registration assigned. Neither seems to have all the details of the actual record setting machine, so probably similar machines prepared by the factory for racing or development. Cyril setup a depot at Brooklands to tune, certify, and sell Sports models for 100mph performance. Perhaps these are a pair of those machines. Both have an unusual box on top of the rear carrier.
-Doug
