I have just finished the biography of Vernon Lee, the 'English' Victorian/Edwardian author. She is generally referred to as English although she was born in France, died in Italy and did not ever live in England. (She would've seen herself as English.)
Her grandparents were a French aristocratic refugee from the Terror, a lady from Southend in Essex, a Jamaican plantation owner and a Philadelphia woman who was the daughter of Scottish emigrants. I can find out very little about these four souls considering they are from fairly privileged backgrounds.
If anyone fancies a challenge in France, Jamaica or darkest Essex, here's your chance...