Thank you Tal for responding to my Query and for your suggestion. I have Marianne MacLean's book and it is one of the best sources on the Scots of Glengarry. Certainly she deals with the MacLeod Settlement but does not follow the genealogies of all the original 40 settler families. I have been over the book including the Index and there does not appear to any specific mention of a Roderick McLeod.
I have used Marianne's book as one of the main sources for my blog post retelling the story of the Glenelg to Glengarry voyage of 1793.http://peersuptonsmithdodd.wordpress.com/
Thanks again for your suggestion,