M'lud, after consulting Victoria's foremost technical expert in this matter, fresh evidence has come to light, I beg leave to present it to youse.
This is from DG's 1972 cattledog and, I think , proves the point that GC's bike in that shot,
IS a circa 1972 Godden Grasstracker with what appears to be an Elstar tank.
The reason the wheels looked wrong, to me , is that it has a disc rear brake and a full width front hub, as the cattledog states, REH hubs were an option that year.
The 1976 Godden catalouge shows the later distinctive Godden drooping rear A frame and REH hubs as standard.
Foss