Hi, We have researched the family tree back to William, he is the cousin, not brother, of Robert and Francis Sutherland. We thought at first they were brothers as they seemed to travel to Gravesend, Kent, together. They are all buried in the cemetery at Gravesend with other members of the Tonge family, there are two a memorial stones. They were one of the four founding fishing families of Gravesend. Would be willing to exchange any details with you.