From a bit of searching in old newspapers, it appears there was a South Elmsall Vikings cycling club which staged road races in the mid-1950s, some of which attracted big names of the day. The event which I've seen most mention of was their Spring Classic, which in 1955 started in South Kirkby, with laps of a circuit through South Elmsall, North Elmsall, Ackworth roundabout, Hemsworth and back to South Kirkby. I didn't find a mention of the exact finish point.
The 1955 event was on 3 April, and next day's Yorkshire Post describes it as dominated by the Hercules professional team: Dave Bedwell won in a sprint finish with his 3 team mates (F Krebs, RJ Maitland and B Robinson), with the rest of the field three quarters of a mile behind. Could this possibly be what we're seeing here? Did the Hercules team wear those colours?