Thomas held the Isle but for a short while when, dying without issue, the property went to the next brother, James.
Source: Robert Halliday Lidderdale, An Account of the Lowland Scots Family of Lidderdale, 1950.
In May 1629 Thomas Lidderdaill had sasine [either the symbolic act of giving legal possession of heritable property, or the instrument by which such an act was proved to have happened] of the five pound land of Galeway.
[O]n the 25th October 1621, and 11th October 1627, Thomas Lidderdale, styled of St Mary, son of James Lidderdale, styled of Isle, had retour of Middle or Meikill Galtway. On the 4th May 1630, Thomas Lidderdaill de Sanct Mary Isle was heir parcener of Magistri Roberti Richardsone, commendatoris de Sanct Mary Ile, avi ex parte Matris. In December 1636, James Lidderdaill had sasine of Torris Grange (Torrs and Grange) and others. In December 1640, we find Thomas Lidderdaill of St Mary's Isle, and James his son.
Source: P.H. McKerlie, History of the Lands and Their Owners in Galloway, 1878.