In the 1970s and 1980s he gained notoriety for a hoax involving the fabrication of the Utopian Sultanate State of Oecussi-Ambeno, located as an exclave on the Island of Timor, with himself as the self-proclaimed Sultan.
Grenville's artistamp output encompasses an entire alternative universe of artistamp countries. These include the Sultanate of Oecussi-Ambeno, the Kingdom of all the Sedang (not to be confused with the historic Kingdom of Sedang), the Sultanate of Upper Yafa, the People's Republic of Kempland, the Free Vinland Republic, the Republic of Liegerland, the Republic of Port Maria, Tui Tui, Aldabra, Karenni, Raoul, the Land of Muggy, Cryonica, Aramoana, Whangamomona, Lar?, Nova Arcadia, the Antarctic Confederation and the Khanate of Bokhara. Grenville's artistamp world even has its own imaginary "United Nations," the "International Council of Independent States" (ICIS). His creations are sometimes identified as micronations; however, being completely fictitious and without "participants", they do not fit the definition.
In January 1999, he came to notice for the discovery of a long missing 1965 original episode of the BBC television series Doctor Who, discovered in a garage sale in Napier; the episode, "The Lion" (the first part of the serial The Crusade) was subsequently released on VHS and later DVD.
- (1999). "Only Chance to See Doctor Who Episode." The Press (Christchurch). April 13.
- (1999). "Bruce Grenville and the Utopian State of Occussi-Ambeno". Takver.com. Retrieved September 6, 2007.