The first day of issue was 7 MAY 1980. There are 6 covers for this series, 5 singles and 1 combination, also I show the envelope from Fleetwood here as well:
Combination / full set
Envelope from Fleetwood (note the artist typo: Roger Rogers instead of Roger Roberts)
Some more information about the artist Roger Roberts from the Unicover website:
Roger Roberts Australian
Roger Roberts graduated from London’s Royal College of Art in 1966 and came to Australia in 1967 after briefly working in the graphics department of the British Broadcasting Company. Roberts moved to south Australia in 1972, despite warnings from colleagues of disastrous financial consequences. After seven years in south Australia, Roberts proved his colleagues wrong, and is now one of Australia’s leading illustrators. Roberts has taught at the Sydney College of the Arts, and has owned his own studio. His Christmas stamp designs include the controversial Santa on a Surfboard, as well as scenes from Waltzing Matilda.