The National Archives of Australia have several files relating to this aircraft and crew including two for F/L Walker. They are digitised and available for viewing online at the following link
http://naa12.naa.gov.au/scripts/Item...=1&O=0&T=I&C=7
Scroll down the page and click where it says 'view digital copy' to view each one.
There may be other files, but these are the results I got with a simple search using 'Walker 419358' in the search engine.
Hope that helps.
Regards
Linzee