This caught my eye because I went to school in Sydney (quite near Parramatta) with a girl who was a Crowther-Wilkinson.
If you go to the National Archives of Australia website,
http://www.naa.gov.au/collection/recordsearch/index.aspxand click on RecordSearch, then type in "Crowther-Wilkinson", select "Phrase" from the drop-down menu, and hit "search" ... you'll find enlistment records for Herbert George (b. Birmingham 13.6.1919, enlisted Cowra NSW, NOK Crowther-Wilkinson, Ruby), William (b. Birmingham 27.5.1920, enlisted Parramatta NSW, NOK Crowther-Wilkinson, Gladys), and Frank (b. Birmingham 5.5.1921, enlisted Leppington NSW, NOK Crowther-Wilkinson, Frank).
None of these has yet been digitised for viewing online, but you can probably apply for copies by using the reference numbers listed.
Also found Frank's death registration (can send you the registration number if you wish to apply for a copy of the certificate) on the NSW BDMs website, : - this gives his parents as George William and Maria. Additionally, there's a death registration for Fanny Crowther-Wilkinson (aged 76, father William) who died in 1967.
Hope this is some sort of help
