St Margarets was No. 80 Tickord Street. Using the 1910 Valuation Survey (Lloyd George Survey) map and register (actual date 1914) I have identified it as the house labelled as Tickford Lodge on this OS map of 1900 (which is the map that was annotated for the survey):
https://maps.nls.uk/view/104180654#zoom=6&lat=1661&lon=12541&layers=BTThe property is recorded as two sites for some reason but Miss Sterling Stuart is recorded as owner and occupier of both. The former sale date is recorded as ca. 1901.
The ground floor includes Hall, Sitting Room, Drawing Room, Dining Room, Servants Hall, Sitting Room [again], Kitchen, Scullery, Pantry, Flower Room. There are two cellars.
The 1st floor has 8 bedrooms, a chapel, and a bathroom. Above that, 2 attics.
The valuation is a little confusing, but I think it has been reduced from an owner's estimate of £2000 to £1300 because:
"House old fashioned – only fair repair, bad approach"
Another building (on the eastern boundary I assume) is a "double coach house, harness room, stable used as coach house" described as "poor repair". A cottage is also listed, but no details.
The plots immediately to the west, marked 277 and 278 on the OS map (but not the houses facing on to Tickford Street) are also owned by Miss Sterling Stuart, but are occupied by James Temple and are listed as St Margaret's Nursery Garden.