Well we eventually made the pilgrimage to the airfield yesterday, being fairly sure it might have gone over night as it was calm and a there was a bright moon. But there it was - slightly to the west of the area marked on the previous post but looking quite remarkably pale in the strong sunlight. Because it was so pale it was easy to see with the naked eye at some distance running around on the dark concrete. Thanks to Andy Sims for help with finding it.
Rosemary Royle