A son of James and Frances has little to be recorded about him. However, in Melton Church near Daventry, Mary his niece, erected a memorial firstly to her grandfather, James M.D. who died on 12 November 1761 aged 85 and to his wife Frances, who died on 1 May 1725 aged 50 (?); then to her father and mother, Nicolas and Helen Child, who died on 19 March 1746 and on 15 May 1775 (Nicolas aged 43 and Helen 69); and lastly to her Uncle John who "tenderly and affectionately supplied the place of a husband and father to his widowed sister and her daughter." He, John, died on 6 July 1775 aged 66 and was buried at Chipstead in Kent.
Source: Robert Halliday Lidderdale, An Account of the Lowland Scots Family of Lidderdale, 1950.
John Lidderdale was a Captain in the Navy who afterwards lived at Sherwood Hall near Mansfield.
Source: communication from Dave Rusell-Smith
John Lidderdale's Last Will and Testament was written on February 4, 1764, and recorded on Novermber 21, 1775. The will names "brother William Lidderdale" and sister Helen Child as the beneficiaries. Because Helen Child was deceased when the will was recorded, Mary Clark (wife of John Clarke) was identified as next of kin.
Source: Public Record Office, The National Archives, United Kingdom (http://www.documentsonline.pro.gov.uk)