I am very familiar with these two suburbs that you have purchased your IP within - fantastic areas in Brisbane.
From my experiencing sourcing PMs for my IPs what is of critical importance is not only the locality of the property management agency looking after your asset i.e. the agency may not be located in the specific suburb of your IP rather the quality of the service, commitment of PMs to offer a great service (workloads have a significant impact here so ask what the caseload of each PM is(APPs can only do so much to save time for PMs) and capability to build fantastic relationships with both landlords and tenants.