It’s a bit off-topic, but the latest issue of the journal Critical Survey is devoted to writer William Le Queux and in particular his novel The Invasion of 1910 (published 1906), which is a notable example of the short-lived sub-genre that Munro also essayed with When William Came: the invasion-of-Britain fantasy (though the authors wouldn’t have accepted the description “fantasy” so readily).
I’ve not yet had a chance to see if Munro’s novel is mentioned in any of the articles.
Normally access is restricted to subscribers and libraries, but all Berghahn journals are available to all until June 30. See here: https://www.berghahnjournals.com/page/covid19/covid19-update
Volume 32, Issue 1-2
William Le Queux, Master of Misinformation: Populism, Invasion Scares and War Propaganda in Britain, 1880–1920
Please visit the Berghahn website for more information about the journal: www.berghahnjournals.com/critical-survey