I had heard and read the story of the civvy canteen manager
being made a Petty Officer so he could man a GPMG but
nothing about the Fleet Air Arm actions.
Further to John Sephton's outstanding bravery, here's a link to put John Leake's own bravery (and his transfer from "Canman" to Petty Officer) into better context
John Leake (DSM) - Wikipedia, the free encyclopedia His former Army service clearly stood him in very good stead.
Jack