William Robertson Lidderdale succeeded to the representation of the family at the death of his father at Castlemilk, in August 1777. He succeeded to Castlemilk, and became a captain in the Scots Greys in 1775, which regiment he joined as a coronet. He sold the property. He married Julia Rae in 1789, and had issue, of whom survived,

    David, died unmarried in 1860.
    Robertson, died unmarried in 1840.
    Julia, married, in 1822, John Forrest of Long Meadow, Annan. She died in 1834, leaving issue,
        John James [Forrest], died young.
        William John [Forrest], born in 1828, of Long Meadow. He married, and had issue. He died in 1873.
            William Robertson Lidderdale [Forrest], born in 1870.
            Julia Isabel [Forrest].
         Andrew Turnbull [Forrest], born 1830. He married, and has issue,
            John Andrew [Forrest], born in 1870.
            Julia Margaret [Forrest].
    Margaret, died 1868, buried at Gata.
    Elizabeth, died 1827.
    Eleanora, died 1824.
    Jane, died 1831.

Source: P.H. McKerlie, History of the Lands and Their Owners in Galloway, 1878.