James Cruikshank inherited lands in Jamaica inherited from his father and shared with his brother, who predeceased him in 1812 (James Cruikshank profile and legacies summary). A death in 1831 means James Cruikshank held slaves in Jamaica for his whole life, something not recorded on the memorial, other than through references to Jamaican property.
A death in 1831 means James Cruikshank died one month before the Baptist War an 11 day fight for freedom of approximately 60,000 enslaved people in Jamaica.
James’ daughter married Charles Cornwallis Dansey. Dansey saw action in the Napoleonic wars and after the death of Mary returned to London where he is recorded as living in Woolwich, He held the position of Chief Fire Officer at the Royal Laboratory, part of Woolwich Arsenal between 1839 and 1846, a period when the arsenal fell behind in research. The 1841 census records him living in Charlton.
Ballards Valley in 1832 is reported as an estate of 307 enslaved people. https://www.ucl.ac.uk/lbs/estate/view/2378.