I would have to agree with Frances that Leslie is not a Manx name, and is more likely to be Scottish. The earliest Leslie record on the Isle of Man is as Frances says for a Thomas Leslie buried in the south of the Island in the parish of Rushen in 1762. No age given. The next Leslie being buried on the Island is in 1813 which I guess is a bit late for you. I guess you could try the Mormon site 'FamilySearch.org' or perhaps start searching for passenger details via a website.