John is mentioned in the Kirkcudbright Town Council Records for the years 1576 - 1604, twice in minor entries but on pages 137 and 138 there is one concerning a marriage contract broken by the woman's death. The entry cites James of the Isle and states he was his father. Neither this entry nor the others say if he was senior or junior to Alexander.

Source: Robert Halliday Lidderdale, An Account of the Lowland Scots Family of Lidderdale, 1950.