The story
Created by author Elisabeth Beresford; they originally appeared in a series of children's novels from 1968. The name was suggested to the author by her young daughter's mispronunciation of the place name "Wimbledon" as "Wombledon" https://www.telegraph.co.uk/news/obituaries/culture-obituaries/tv-radio-obituaries/8226039/Elisabeth-Beresford.htmlhttps://www.tidybag.uk/people/interview-with-elisabeth-beresford-daughter/. The books centre on the activities of a group of the creatures who live on Wimbledon Common.
Etymology from Wiktionary, CC BY-SA 4.0.