Through an odd turn of events I ended up staying in the village where my 5th great grand aunt Mary Freeman is buried. We uncovered her memorial stone under the altar at the village church, which describes her unusually as having died after 'a life of purity, piety and benevolence, and after having borne a long and painfull illnefs with truely Christian resignation and fortitude'. She had a brother John and sister Sarah and, confusingly, her parents were also John and Mary Freeman.
The link to my paternal grandparents is through Mary's sister Sarah, who married Edmund Lincoln, governor of the South Caribbean and St Vincent 1783-87. The mystery continues!