I found this website: http://www.leachianus.com/

It still doesn't go into the differences of the localities beside them beside the GT species is larger. Here's how they broke up the Grande Terre to the Offshore.

•R. leachianus leachianus (Grande Terre): Poindimie, Mount Koghis, Yate, Mount Humboldt and Riviere Bleue
•R. leachianus henkeli (Offshore): Isle of Pines, Menore, Bayonnaise, Moro, Duu Ana, Nuu Ana, Nuu Ami, Koe, Brosse, Caanawa