Sullivan then prevented the opera from being produced, for several years, although other producers were interested in reviving it. Allen quotes a letter of 22 June 1877, in which the composer wrote in the third person, "Mr. Sullivan begs to inform Mr. Cowper that the 'Zoo' has not yet been published, nor will it until considerable alterations have been made." In a letter to his friend Alan Cole on 22 November 1877, he wrote, "They want to revive the 'Zoo' at the Strand. Will you rewrite it with me?" Both letters suggest that the composer was less than satisfied with what he had done in 1875. The final production of the piece during Sullivan's lifetime was at the Royalty Theatre from 14 April 1879 to 3 May 1879, with Lottie Venne as Eliza and W. S. Penley as Mr. Grinder. Sullivan is not known to have made any of the revisions he had contemplated in 1877.