This image is a section of the photo of cars on the grid at Ohakea 1955. In Vercoe's book it is said to be the Ohakea Trophy Race but I have two references that show car 37, P J Harrison's Cooper Matchless, was a non-starter in the Trophy race. Therefore I believe the photo shows the start of event 6, the Sports & Racing Car Scratch Race.
Both my references show Jack Edwards as a late entry in car number 68. I reckon that car is the one on the far side of the track, immediately in front of the group of four men. Only the 8 of the number is showing but the actual car 8 is on the back row of the grid (not shown in my portion of the photo). In the grid positions shown in Vercoe's book Edwards is next to car 30 (G Brown's Buckler) and in front of car 58 (Bruce McLaren's Austin 7 Special). That ties in with the photo.