rolling20, I had known the chap who was killed when he released both seat harness and parachute - but only as a fellow ULAS student many years earlier.
I can't remember the exact procedure we used when I became a Bulldog QFI in 1991, but the fatal accident was still quite fresh in peoples' minds and some procedure had been adopted to reduce the risk of inadvertent chute QRF release during a real abandonment.