Yes, characters with the Cayley surname exist in fiction! We get everywhere. If you can add to this list, please send me a message via the contact page.
- Grant Allen, Miss Cayley’s Adventures, 1899 – a late Victorian romp in which, among other things, the intrepid Miss Cayley defeats Prussians in a mountain-cycling race
- Sydney Arthur, A Man’s Worth, publication date unknown – described as a “bizarre college romance” in Death So Noble: Memory, Meaning, and the First World War – Book by Jonathan F. Vance; University of British Columbia Press, 1997
- Elizabeth Chater, Miss Cayley’s Unicorn, Fawcett Crest 1988 – a Regency romance with a plot unlikely in the extreme
- Stanley Middleton, Blind Understanding, Hutchinson 1992
- Garrett Mill, The Colonel Sahib, 1902 – about a special service officer Colonel Cayley in an Indian Service state in a time of famine when rebellion is threatened. The Colonel takes steps to undermine the rebellion before it erupts.
A A Milne, The Red House Mystery, 1922 – the only crime novel by the author of the Wiinie-the-Pooh books, in which a Cayley is a villain
- May Sinclair, The Helpmate, 1907 – in which newly-wed Anne Majendie finds out that her husband has had an affair with Lady Sarah Cayley: Anne’s first words in the novel are “Who is Lady Cayley?”
Several of these are available for free download from sites like http://manybooks.net.