Brooksby sat on the Darling Point allotment that spilled east toward Lower Ocean Street — the edge that later reads as Double Bay’s Ocean Avenue rather than the Greenoaks Avenue ridge. Dictionary of Sydney places two solicitor-politicians here in the 1850s: Robert Ebenezer Johnson at Brooksby and James Norton at neighbouring Ecclesbourne. Johnson, named to the first New South Wales Legislative Council in 1856, made Brooksby his home until his death in 1866.
That is the civic heart of the house. Later it did quieter work as Mrs Robinson’s preparatory school for boys — one of those small eastern-suburbs academies that filled the big rooms when the original families moved on. A 1930s photograph in Woollahra’s local studies still shows tennis on the lawns at what the catalogue calls 45 Ocean Avenue, Double Bay. The mansion itself is gone to subdivision and flats; the name survives in the local-history file.
Walk from Greenoaks Avenue down toward Ocean Street and you are tracing the old estate edge: Mort’s Greenoaks (Bishopscourt) up the hill, Brooksby and Ecclesbourne on the eastern fall. Cross-link the Bishopscourt post for the Gothic neighbour; this page is the solicitor’s house on the Double Bay side of the same story. (And yes — fix the titles “Double Bay” while you are there.)