Thanks for your question Natalie. There are a number of ways to to find schools that meet your needs. You could visit the Sydney Central and East section. There you will find every non-government school in the region. The filter tool on the page will narrow down the list to only those that meet your criteria. Or, you could try the Sydney schools map which displays every school in Sydney. Enter an address to show only schools within your chosen radius or simply zoom down. You'll find you can click on any school's marker and see details about the school. I have included some links below to the pages I've mentioned.
Both Reddam House and International Grammar School can be found on those pages.

One of our friendly help desk staff also will be in touch to offer further assistance.