Gerrard's cagy DNB entry implies that Sansom was a demi-mondaine avant la lettre, attacked by Eliza Haywood for her immorality. She was the daughter of a Catholic gentry family, and it's unclear what she did in her twenties before marrying Arthur Sansom. Perhaps the poetry would say more--she reminds me a bit of Pilkington (also reminiscent of Pilkington is that there she seems to live on as a scandal figure in the posthumous Clio (1752)).