Andy,
I think this refers to the passing of the Group Vache category, shortly before the introduction of Groups C1 and C2.
Those mothers could really move. The sight of the full grid pounding across the start line at the rolling start, hooves thumping, udders swinging would raise the hackles on any man, and send his testicles to places they hadn't been since leaving primary school. I am told the noise was staggering, rising above all the fizzing celtic bungholes, but ultimately the category was doomed to failure. Not least, the pong was f*****g staggering, and total loss of traction on some of the corners led to some nasty offs. And then there was the franchise problems with the local burger and frites boys, I believe in it's penultimate year someone ate the race leader.
Hope this helps.
H