I am able to reveal, now that the cloak of secrecy has been lifted, that the Wiggins Aerodyne was the photographic 'chase' aircraft for the Shack formation loop.
This sortie was doomed from the start; due to the incredibly high cockpit vibration levels experienced in the Aerodyne (see an earlier post of mine on another thread), it was impossible to capture any images in the dark, despite the best efforts of the Observer/Box Brownie/Ever-Ready Torch combination.
Tragedy ensued when the Mighty Shacks pulled up into their majestic loop by moonlight; the dismal performance of the Aerodyne was such that Avro's finest were on the downside & pulling through their start point before the Wiggins contraption had changed attitude to follow them. As the lead Shack went straight through the struggling Aerodyne, the Shack captain merely thought that he had encountered a flock of moths, lured by the siren glow of the formation's lights; a quick flick of the windscreen wipers, and normal vision was restored.
This sorry episode was yet another calamity in the troubled history of the Aerodyne.
(Q: What is the correct collective noun for moths? Is it a 'De Havilland' of moths?)