Research has identified Lady Elizabeth Monck as Elizabeth Araminta Gore (1770-1845), a daughter of Sir Arthur Saunders Gore, 2nd Earl of Arran. Although in 1783 Elizabeth married a commoner, barrister Henry Monck, she retained her courtesy title of Lady Elizabeth.
Lady Elizabeth was evidently a beauty of her day, as evidenced by the following quotation from a letter of August 1818, written by Sydney, Lady Morgan to Lady Clarke; "We only wanted the Hon. Mrs. Browne, who was married about the same time, when, lo! she entered with her mother, the beautiful Lady Elizabeth Monck, another of the charming clan of Arran, who for grace and beauty, when they were in their prime, could not have been matched in Europe. Lord Arran ought to have had some prize for the specimens of physical perfection he gave to the world in his daughters."
Lady Elizabeth had two daughters, the elder daughter, Elizabeth Araminta Monck married Vice Admiral Sir Charles Paget (1778-1839). They had a number of children including a son, Henry Horatius Paget who died in Malta in 1828.
Sir Charles Paget was one of several famous brothers, the eldest of whom was Henry Paget, Earl of Uxbridge and one of the Duke of Wellington's commanders at the Battle of Waterloo. Another Paget brother was Ambassador to Russia.
It therefore appears quite reasonable to expect that Lady Elizabeth Monck did meet Marshal Ney during Ney's trial after Waterloo, and could have asked him for a souvenir of Napoleon. For more on this portrait see a more detailed entry in the European 1 section of the collection, but also note the oil version by Duchesne here.
The second daughter of Lady Elizabeth Monck, was Catherine Anne Isabella Monck who married Dominick Brown 1st Lord Oranmore. Their daughter was Henrietta Araminta Monck Browne, see associated miniature portrait of her.
Lady Elizabeth Monck had a Grace and Favour apartment at Hampton Court Palace from 1829 to 1845. As an interesting aside, there is a reference to Lady Elizabeth Monck as a widow, at The Proceedings of the Old Bailey, London 1674 to 1834 in 1826 when a young man called William Andrews, was found guilty of stealing a bundle of laundry worth two pounds, from Lady Elizabeth. He was sentenced to be transported for seven years, probably to a penal colony in Australia. 830