Susannah was born in 1753 in
Hamburg. She was the daughter of Jacob and Elizabeth Bosanquet. Her father was a director of the
Levant Company and the
East India Company. Her grandfather David Bosanquet was a
Huguenot who had left France in 1686.
Jacob Bosanquet was a sibling. She married James Whatman (1741–1798) on 3 December 1776. He was the son of
James Whatman (1702–1759), with whom he had created an innovative paper business in Kent. Her husband had been married before to Sarah (born Stanley) who had just died. He had two children from that marriage, Camilla, who married Sir Charles Style, Bart. and Letitia, who married Susanna's cousin, Samuel Bosanquet of Dingestow Court, son of the Governor of The Bank of England. , Kent, with Mr. Whatman's Turkey Paper Mills" by
Paul Sandby in 1794 including when they moved to "Vinters" There is a painting by
Paul Sandby which shows Vinters in 1794 and the paper mills that had created the family's income. Her husband died in 1798 having sold the mills years before when he had a stroke. Whatman's son, James, married his cousin, Eliza Susanna Gaussen, daughter of Samuel Robert Gaussen of Brookmans Park, Hertfordshire. ==Death and legacy==