Angus Livingston(e) and Margaret McPhail c. 1790's?

[Keith Livingstone Australia]

The professional genealogist Stuart Reid at Scottish Roots has taken my Livingstone male ancestry back to Angus Livingstone ("Chelsea Pensioner, deceased") who married Margaret McPhail. Their son John Livingston(e), a weaver, was born b/w 1796 and 1806 in Mull. He married Agnes Edmiston/Edmonston on 28/10/1827 in Livingston, and he died 6/7/1858 in Tervagan, Kilmeny. We can't go back any further on this line through existing records. Anyone out there have info from other sources?