Dan,
It would have been around '85, but can't be precise...I've slept since then. And, yes, I do believe the incoming Groupie was one of the participants...however, see clause one above.
Mad Jock,
Either or both of your ideas make perfect sense. I can't comment on the tow bars in use today, but I don't remember anything sensible like your ideas in use. Maybe there was but I was just in attentive.
Camlobe