InshaAllah will do.
Every case is different; however, the trend is that first visa office (Sydney) will take approximately 6 months to process your eligibility and to see if all documents are in order. After that they might send your application to London to check if the marriage is genuine and to see if the principal applicant is eligible.
See my timeline to get an idea:
Application received: June 17, 2019
AOR1: August 07, 2019
Sponsor Approval: August 14, 2019
ECAS says in Progress: August 14, 2019
Biometrics Requested: August 14, 2019
Medical Requested: August 14, 2019
Additional Information Requested: August 14, 2019
Biometrics Given: August 20, 2019
Medical Exam: August 29, 2019
Medical Passed: September 03, 2019
Additional Information Received: September 05, 2019
File Transferred to LVO: November 12, 2019
AOR2: November 15, 2019
