I recall that i was 13 years old, and it was a heli with "marlboro" plastered on the side..so i guess it was a sponsors heli.
It was right in the middle of Marillions "VERY" boring set...which most people were having a snooze too...or was that the beer.
My memory doesnt serve me that well, but seem to think that it was a Bell 206.........don't quote me on that though.
Am guesing that the ANO's fabulous rule 5 and its many paragraphs would now put paid to that ever happening again............and yes, it was quite low..........somewhat lower than 500ft, and over the crowd line and stage area.......Happy Days.!
I recall they did it also in 1983 at a similar gig.........but i was too young to recall that in detail.!