i have learned that ethel larcombe was part of the glasgow art scene and worked for talwin morris at blackie's publishing. in fact, one of her designs has already been posted right in this very blog, as was kindly noted in the comments section. (added on the 24th)
yesterday's post of the cover of the studio (below) prompted margaret to ask who had done the artwork. i wrongly guessed will bradley, and then jalf pointed out how much it looked like something pre-raphaelite.
i have now spent two days online and in several dozens of my books, and i think i finally have the right answer: ethel larcomb.
i have still been unable to find an accredited version of that actual cover (which i think was on every issue of the magazine), but i have found, among others, these two images which are attributed to her. i think the facial shapes, the decorative elements, and the backgrounds make it pretty clear that the image below was hers.