Just one windmill painting stamp we can't identify

Early last year, Fred Atkins of the Windmill Study Unit asked for my help in identifying some windmill paintings that had been turned into (fake) postage stamps (aka cinderellas). At the time he provided a number of images, including one that had a stamp as the inner part of a sheetlet, with another windmill painting surrounding it. Although I identified the stamp itself, I failed to identify the outer painting.

Fred's having another push to try and identify that elusive painting, and has provided a second image, where the outer image, in mirror reversed form is actually used on the stamp itself. He's posted to Mill Writing at the Mills Archive, (using the original dual image) and I've also included the second single image here. Unlike the other paintings, which were "classic" works of art (with quality photo reproductions sourced via the Corbis stock photo library), this remaining painting is rather more primitive - almost a cartoon image of a Romany style caravan in front of a river and a cottage, with a post mill in the background. It could almost have been grabbed from a greetings card - I very much doubt that it represents any real scene.

Having tried to identify the stamps then, I wrote a technical follow up article about how I went about it. Google have just upgraded their image search service to include searching by providing a source image to search for, which provides another outlet to try which was not original at the time - but that fails to come up with any answer in this case either (and I have tried searching for both the original and mirror reversed forms).