In 1798, the family moved to Hamburg in an attempt to escape creditors, where Mary's brother William Leman Rede was born.

[1] That year, her husband died, and she moved to Hobart in Van Diemen's Land with her sister Lucy, and her brother-in-law.

In this last novel, she included a postscript in which she set out her view of women's rights, which had developed through her participation in a circle around the Unitarian South Place Chapel.

[1] During the 1830s, Grimstone was active in Robert Owen's socialist movement, writing frequently for his New Moral World newspaper.

Leigh Hunt included her in his poem 'Blue-Stocking Revels' in 1837 and she may have been the basis for "Lady Psyche" in Alfred, Lord Tennyson's The Princess.

When the People's Journal closed in 1851, she stopped writing, and lived off an annuity until 1869,[1] when she died in Paddington from swallowing disinfectant.