Thanks for all yours, Jocelyn and Sue.
Walter was clearly a prominent amateur thespian in Auckland (while running his Queen Street butcher's business: http://paperspast.natlib.govt.nz/cgi-bin/paperspast?a=d&...
Also I notice in the letters of Robert Louis Stevenson (letter 2159, page 287, April 1889, Vol Six, Yale UP, 1995)that RLS wrote admiringly from Honolulu to DCM: "... I wish to thank you, and to congratulate you; setting aside George Meredith, our elder and better, I read none of my contemporaries with the same delight..."
And in a footnote, the editor, Ernest Mehew, notes that DCM, in his response, having thanked RLS profusely, explains that he cannot pass on RLS's message to his wife, as "the poor thing suffered dreadfully for years and took refuge in opium and brandy... and now for two years I have not seen her."
DCM appears to have taken up with Alice in Melbourne in 1891, three years before the divorce proceedings.