Printed by The Bell & Baker Press: 'A limited edition of 20 copies published by the author'. According to the artist's son's website http://www.happydragonspress.co.uk/history.shtml the total print run was in fact 19 copies.
This example bears the imprint 'A Grove Edition' which would seem to indicate that it represents a posthumous re-issue by the artist's son (confusingly also named Julius) from the latter's Grove Press in Muswell Hill.