The 456 Squadron ORB is online at the National Archives:
www.naa.gov.au
Do a record search on 456 Squadron, click on "digitised files first" and you should see it. Has records of all aircraft and crews to sortie on any given date.
Not sure if the 455 Squadron ORB is there too or not - wouldn't be surprised if it were.
Edit - Yep, 455 Sqn ORB is there - "Unit history of number 455 Squadron - June 1941 to May 1945", make sure you click on "enlarge" (instead of "read") to see the pages clearly.