In answer to a post in 2005, if the poster is still about(!) Always Argyll was written by Duncan McCrone. I believe it was Valerie Dunbar who had a popular recording of it, apart from Duncan himself.
And another song about the Highland Clearances in Sutherland, The Braes of Sutherland by Ivan Drever, on the Wolfstone album, Year of the Dog. (Not to be confused with Jim's song, The SHORESof Sutherland.