In the later 1890s, Coates left the stage for a medical operation on his vocal cords and further study, and reappeared as a tenor in light opera in 1899-1900 at the Globe Theatre in London. He first appeared at the Globe Theatre in "The Gay Pretenders" in November 1900 and then at Covent Garden Opera House to create the role of Claudio in Charles Villiers Stanford's four-act opera "Much Ado About Nothing" in 1901. Here he was in enthusiastic company with Marie Brema (Beatrice), David Bispham (Benedick), Suzanne Adams (Hero), Pol Plançon and Putnam Griswold, though the press did not much appreciate the value of the work or their efforts. This was followed by Gounod's "Faust", this time in the title role. That year he also appeared in the "Gürzenich's Concerts and Opera" at Cologne and at Leipzig.