Naming another Australian County-class cruiser

What might Australia have named an additional London-subclass County-class cruiser?

Sydney or Perth are proposed as the likeliest choices, based on city seniority and the names already used by Australian cruisers.

Australia and Canberra already occupied the names of the existing County-class cruisers. Brisbane, Melbourne, Sydney and Adelaide had also appeared on Australian ships of the 1910 Town-class lineage. Melbourne and Sydney are identified as 1913 ships, Brisbane as a 1916 ship and Adelaide as completed in 1922. Sydney or Perth emerge as plausible choices for the hypothetical additional cruiser. This is a naming inference from city seniority and existing usage, rather than a documented selection.