1856 Archtiect Lloyd Tayler tenders for 2 large family residences with offices, stables etc at StK for Capt George Gilmore. Argus, 27 Oct 1856, p 7. MMDB
1858 St Kilda rate books both owned by Captain George Gilmore.
The Vardy plan of 1873 shows them as two lots, numbered 8 and 9 Princes Street, and the owner of both lots is still Gilmore.
1878 was turned into a single house : Argus, 4 Mar 1882, p 5 , "sale of mansion of George Robinson, Princes St, St Kilda, thoroughly renewed in 1878 under supervision of Lloyd Tayler at a cost of over 3,000 pounds, large entry hall, drwg rm 24 x 16, brkfst rm. mrng room, dng rm 24 x 16, library, 2 large bedrs 24 x 16 about 15 ft high, 12 smaller bedrs, 3 bthrms, etc." This sale apparently not successful as Robertson stiil there in 1897. MMDB
1894 MMBW map shows them as one house, with no central property line, and one driveway.
In 1922 a self contained flat at this adress was being advertised, so it seems likely the conversion to flats happened before then.
Appears to be still one owner in 2026, since flats only listed for rent rather than for sale.