The air-gunnery training range - most likely tis is either Penrhos or Porth Neigwl - in 1941. That looks like a Boulton Paul gun turret on the road trailer. The aircraft silhouette is on a narrow-gauge flat waggon, which is rope hauled. This mobility gives the trainee gunner practice in deflection - the art of shooting where the target is going to be when the bullets arrive. [Not always easy, especially when you are moving as well, and not in straight & level flight].
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