"Pearlies" are also mentioned in the British musical-comedy, "Me and My Girl", originally staged in the late 1930's, a starring vehicle for the English Music Hall performer, Lupino Lane (believe there was a film too?), and it had a revival in the late 1980's.
British actor / comedian Steven Fry worked on the book revisions for the revival.
A major element of the plot conceit is that the lead character, a "pearly" from Lambeth, is heir to a minor title and land in the country. The starchy relations and hangers-on are appalled. Hilarity ensues.
Usual "Fish-out-of water / topsy-turvy" sort of show.
A hit song came out of the show ( or was incorporated into it), "the Lambeth Walk".
https://en.wikipedia.org/wiki/Me_and_My_Girl 