Re the Valley fatal, subsequently, Training Command refuellers had their product markings doubled in size, Avgas vehicles were to be segregated when parked and if possible dedicated routes to and from the refueller park. Later the open line hose end nozzles were modified to prevent them being inserted in the wrong a/c. I know at the Shropshire flying club (just outside Market Drayton) we quickly got shot of our Avgas, as Gazelle had replaced Sioux.
PM