For the background to the extended Hall-Dare family (in 1912), see Sir Bernard Burke, A Genealogical and Heraldic History of the Landed Gentry of Ireland (1912, London, pp. 165-6. Mabel is listed as the second daughter of Robert Westley Hall-Dare, marrying Theodore Bent in August 1877.
For Mabel’s maternal family, the Lambarts of Beauparc, Co. Meath, see Burke’s Genealogical and Heraldic History of Peerage, Baronetage and Knightage (1914, London, pp.1151-2).