Note: the horses and hunters are the other side of the fence.
In those days a simple wooden fence was sufficient to keep out spies, saboteurs and other riff-raff - particularly when an airframe was on a remote pan for an engine run. The fox, as can be seen, has nicked through the fence leaving the hunt to look on in exasperation as it makes its getaway.
Chain link fences and barbed wire only started to appear in the early 70s when Paddy started taking pot shots.
Now what could be simpler?
Nothing to see here, move along please.