Sydney is a patchwork of councils, and Google reads it that way. Parramatta is a City of Parramatta search, the Inner West is a council of its own, the North Shore spans several, and the Sutherland Shire has its own identity and vocabulary.
Apartments and strata schemes make up most of the inner suburbs, while outer council areas such as Penrith are mostly houses, so the same service is searched for differently in each. realestate.com.au and Domain own the listing searches, and no firm's own page will beat them there.
Where you can win is on service and suburb searches, plus the map results at the top of Google. Agents work under NSW Fair Trading rules and trades hold NSW licences, so the proof on your page must be genuine.
GST at 10% shows separately on invoices.