This is the footnote to Bonhams' e-catalogue entry, "Cecily was the second daughter of Sir Walter Spencer Stanhope (1827-1911) of Cannon Hall, Yorkshire and Elizabeth Julia Buxton (1831-1880). Cecily was born at the family estate in Barnsley, which had been the seat of the Stanhopes since 1660. The Barnsley 'fairyland', still visible in the grounds today, was designed by Cecily in conjunction with her father.
Cecily's lineage was fundamentally an artistic one. Her uncle, John Roddam Spencer-Stanhope (1829-1908), and her cousin, Evelyn De Morgan (1855-1919), were heavily involved in the Aesthetic movement. Cecily's elder sister, Gertrude (1857-1944), was a sculptor and painter and is thought to be responsible for the oil panels in Christ Church, Isle of Dogs, executed in the style of Burne-Jones.
On 24 October 1899, Cecily married Major-General FitzGerald Wintour, CB, CBE, (1860-1949), the great-grandfather of the current editor of US Vogue, Anna Wintour (b.1949)."
This portrait does not reveal if Lady Cecily is wearing shoes or Prada shoes.
There is a brief genealogical summary of her here. She is not covered in thepeerage although her progeny are.
From the Bonhams Web site.