I am one of Iain Mac Lachlan's sons, so I can put you all right and stop you guessing about the origins of the song, and the spelling of Iain's surname. My father originally composed the tune in 1958 as a pipe lament for a local doctor who lost his son at sea, under the title Dr. Mackay's Farewell to Creagorry. The tune achieved widespread popularity after it was later used by the BBC as the theme music for the TV series 'The Dark Island' filmed on Uist in 1963. Words were added by the writer and producer David Silver and since then the tune has been recorded by more than a 100 different artists and bands worldwide. No-one played the tune better than my father himself, first as a pipe lament and then in waltz time, and I still have to hear it played as it should be...
My father was the greatest three-row button-box player in the Highlands and Islands and with him died a part of traditional Island music.