My (maternal/maternal/paternal) great-great-grandfather, Charles deCerqueira Lima, Sr. was born in England. Family tradition holds that his mother (who appears in a portrait I own that might have been painted by Sir Thomas Lawrence) was the wife of the Brazilian ambassador to the Court of St. James in the early 19th century. According to that same family tradition she was the belle of London society at the time, albeit she had a weakness for intoxicating beverages.
If anyone knows how to research Brazilian ambassadors to England between 1800-1850, I'd be grateful. I don't speak or read Portuguese, unfortunately, thus Brazilian sources I earlier tapped weren't helpful.