Sidney Stanley: A Query

My Lesser-Known Writers entry (from 2013) on the artist Sidney Stanley (1890-1956), linked here, has attracted a good amount of attention over the years.  Recently I got a query from a person who owns four original watercolour works by Sidney Stanley. The four pictures are related, and may perhaps have been done as illustrations to a book, or to some story in some periodical. But we don't know, really, and it's entirely possible the art was never published. With permission of the owner, I am presenting one of the four here. (Click on the illustration to make it larger.)  It is titled "The Gunpowder Factory"--a related image is titled "The Firework Factory."  The other two pictures are similarly associated,  "Teapot Factory" and "The Tea Ceremony." The strange-looking figures, with long faces and long noses and a single high curl to their black hair, are common to all four illustrations. Are these supposed to be elves of some sort (even their shoes come to curled points)?  Do these ring a bell for anyone?  Comments welcomed!