Is Jean Kerr's best-known book Please Don't Eat the Daisies (1957), or Rory Emerald (1968)?

No, Rory Aloyious Emerald was a real-life author who wrote the similar but skewed book Please Don't Eat the Goldfish Skins (1966). It was an instant success among the piscine Beatniks, and he wrote the follow-up novel, A Streetcar Named Goldfish the following year.