FYI for people worried about travelling after passing test and before receiving approval.
Applied 22/12/17
Passed test 6/1/19 Tweed Heads but live on Gold Coast
Leaving for an unknown period 31/3/19 to see family in UK. Called citizenship helpline today to inform of travel. They were super helpful and reassured me they would just contact me via email / immiaccount if they needed anything. They said they don’t pause application but just asked me to upload any documents (flights & any official documents for reason of extended period if it gets to that)
Relief! I was super worried about this as have been told many times you have to be in Australia when they make the decision.
Hope this helps :)