Sandycove Avenue forms three sides of a rectangle, the fourth (south) side being bounded by Sandycove Terrace (which is part of Sandycove Road). Originally, Sandycove Avenue East was a cul-de-sac, leading to the Martello Tower (Joyce's tower, Sandycove), and is so depicted on maps of 1820
By 1860, there appears to be only 2 houses on Sandycove Avenue East
Ten years later, there appears to have been quite a bit of building, including 3 houses designated as Ellerslie Terrace, as well as a mix of detatched and terraced houses on the east side of the road.
By the time of the 1901 census, there are 27 houses there, of which 5 are vacant. 5 are classified as First class. There are 98 occupants.
The first meeting of the Dublin Bay Sailing Club took place in 1884 in No 7 Sandycove Avenue East, in the house of Major Edward White
St Kilda's, a villa-style house on the East side of the road was the house of Francis Falkner, Grocer, with shops in Grafton St and London. He was there in 1901, but I could not find him in 1911 in any part of Ireland.