From the always useful Lost Hospitals of London: "The St Francis Hospital for Infants was founded in a small house in Hampstead {6 Denning Road} in 1903 by Helen Levis, {first} wife of the industrial chemist Sir Robert Mond {son of Ludwig}, and Dr. Ralph Vincent. ... a year later, its name was changed to The Infants Hospital ... Following the death of his wife in 1905, Sir Robert Mond financed a purpose-built Hospital in Vincent Square as a memorial to her." There you can also read how it expanded, amalgamated, got renamed and closed.
The photo looks posed to us, and those hats!