'Gate heights' indeed. I was at Barton that day, but had taken the opportunity to sneak out to the north in the Chippy just before the Mossie display (which I'd seen many times before). I was about 7 or 8 miles north, aerobatting at about 3000 feet and still on the Barton frequency which had gone quiet as radio frequencies do while an aircraft is actually displaying.
As I pulled out of a loop the radio came live with "the crash is just to the west of the field" made to a Navy helicopter which had got airbourne to assist if possible. Turning south I could clearly see the column of smoke, and couldn't at first work out what had happened. There were several aeroplane in the area, and my first thought was that it was one of them that had come to grief - it couldn't be the Mossie because its display is just a benign series of fly-bys with wing-overs at each end. But subsequent transmissions soon confirmed what had happened.
I flew back to Barton somewhat in shock, and made a wobbly landing just before the field was closed.
Several experienced aeros pilots were commenting on the wing-over technique employed in the display, and when I saw the many videos of the display and the accident I was surprised that no mention of that technique was made in the subsequent AAIB report.
The only saving grace was that when it went so tragically wrong, it did so at the western end of te display over Barton Moss. If it had happened at the Eastern end, over Eccles, it could have been a whole lot worse.
SSD