In her article on the Emes and Barnard Ledgers in The Proceedings of the Society of Silver Collectors, Vol.II, p.169, J. Banister notes that this form of cup and cover, known as a 'wavy shells' cup, was 'of a pattern particularly popular in India'. The Calcutta firm of Hamilton and Co., whose mark appear on the base, were important clients of Barnard's and the name of their agent in London, Thorpe, appears in many of the accounts. Hamilton and Co. was founded in 1811 by Robert Hamilton (circa 1772-1847), although his interest in the firm came to an end in 1817, having returned to England in 1812.
The firm continued with new partners, retaining the name and was one of the most successful of the Indian colonial silvermiths, producing a wide range of pieces of fine quality. As Judith Banister has points out, op cit, they supplemented the locally produced pieces with London-made work which they imported and often stamped with their own marks. The present cup, cover and stand is almost certainly from this group.
For a pair of cups, covers and stands of very similar form, also by a combination of Barnard's and Hamilton and Co., see Christie's London, 31 March 1998, lot 46.