Ha ... Formeco got me in. The series was called PROTOCROSS!!
Well done ! I don't know much more about it - the photo is from 1970, and the events were held in the Hauts de France region, up near the border with Belgium. I think it was just a bunch of friends who built and raced these cars, rather than being a formal ratified series.
Perseverance again TT ! I like it.
PS 200 points and rising.