Yesterday, I accessed the work of M Vine published in The Europeans: emigre artists in Australia 1930-1960, edited by Roger Butler, 1997. She states that Joseph Mann was the jeweller responsible for making the wattle brooch. Oral history indicates that he had previously worked for Cartier, but no definite proof is given for that. Vine says that from 1927 to 1948 he worked mainly in France.
My research, based on immigration documents, shows that at least his wife was in Hungary in 1942 when their son, Charles, was born. By at least 1947 she was in France in Biarritz, where their daughter was born.
On the weekend, I applied to have Mann's naturalisation papers digitised, but it will be a while before that is processed. Vine has looked at these papers and says that he was sponsored to Australia by Phillip Nutt of Select Jewelllery Manufacturing Co, Melbourne. Sometime before June 1953 Mann had purchased the business, and around April 1958 sold it to another Hungarian born jeweller. Mann then went to the US.
According to Vine there are 2 designs for the wattle brooch held by the National Gallery of Australia. Only one is available to view on the gallery's website. It is a design made in 1952 by Ross Allan, presumably for the intended tour by King George and QEQM.
This design shows so many similarities with the design of brooch as it was presented in 1954 that I think we should include Allan's name when mentioning the designer. Without naming any designer, Vine says diplomatically that the design was a collective effort. As can be seen in the drawing from the National Gallery, there have been changes. Ross Allan's earlier design http://artsearch.nga.gov.au/Detail.cfm?IRN=67472&PICTAUS=TRUE