Thank you for submitting your item for appraisal. This appears to be a serigraph by Richard Dunn, done quite early in his career. Richard Dunn was born in 1944 in Sydney, Australia and studied architecture at the University of New South Wales, sculpture at the National Art School, Sydney, and painting at the Royal College of Art, London. He exhibited the world over. Today he is Emeritus Professor of Contemporary Visual Art at the University of Sydney according to his website.
Few paintings and watercolours by Dunn were sold at auction, no serigraphs. The estimate is based on these few results.