On this day 3 October1952

On this day 3 october 1952 The first British nuclear bomb test took place at Montebello Islands, Western Australia.

Dragonfly helicopters from the escort carrier HMS Campania flew over the site very shortly after the explosion. One flown by Lt Cdr Denis Theodore John Stanley, of Thruston, Andover, and Observer Herbert John Lambert (42), of Carnoustie Angus, collected samples of sea water to be tested for levels of radioactivity. (The Mercury, Hobart 4 November 1952) 

This YouTube video covers the story of Op. Hurricane. You can see three dragonfly helicopters 26 minutes and 22 seconds in. It was a public information film and the transcript is available here.

Report in Australian paper ‘The Mercury’ 5 Aug 1952 “Montebello atom tests may be next month”
Report in Australian paper ‘The Mercury’ 1 Aug 1952 “The ‘What is it?’ ship”