They were also cousins of the French family, French Park Estate, Boyle, who were created Baron de Freyne.
One of Gereau's foster brothers, Leopold Adelbert Augustus Ffrench, moved to Mexico and a grandson Leonardo I. Ffrench serving in the diplomatic corps eventually became the Director General of the Institute for Mexicans Abroad of the Secretaria de Relaciones Exteriores.
His father was Major St. John Lucius O'Brien Acheson ffrench Blake (1889-1917), who was killed at the First Battle of Gaza, and his mother, Doris Kathleen Tweedie.