Technically he was two-and-done (he's introduced in the opera case and then gets a case of his own next episode) but yeah, He Does Not Linger, Miss Fisher (and Miss S) are both like "WELL it seems like you and your communist fiancee are perfect for each other after all! and either way she apparently doesn't have another job and I've apparently hit my limit on hiring new side characters of the week to work in my household so ... yeah ....."