The arms are those of Mercer impaling Stewart for Sir James Mercer of Aldie, a burgess of Perth, who married in 1648 Jean, eldest daughter of Sir Thomas Stewart of Grantully.

Sir James Mercer, whose London house was in Axe Yard, Westminster (where Samuel Pepys had lived between August 1658 and July 1660), was appointed a Gentleman Usher to Charles II in January 1661. His only son Charles was christened in June 1667 in the presence of his godfather, the king, whose gift of 80 ounces of gilt plate to mark the event is recorded in the Jewel Office accounts (National Archives, LC5/107, p. 119). Writing afterwards to his father-in-law, Mercer recalled 'that His Majesty on the occasion was very jovial, without any sort of drinking,' except to the child's health (Sir William Fraser, The Red Book of Grandtully, Edinburgh, 1868, p. cxxv).

The maker's mark HW, two pellets above, escallop below in escutcheon-shaped shield, has been recorded on an otherwise unmarked Charles II silver two-handled porringer and cover of about 1670, engraved with the arms of Ralph Cotton of Bellaport, co. Salop and Newcastle-under-Lyme, which was sold at Sotheby's, London, on 24 March 1960, lot 40.

This maker's mark is now attributed to Henry Walsh further to Christopher Hartop & David Mitchell's research.
Silversmiths in Elizabethan and Stuart London, Their Lives & Their Marks p. 336
 

Sir James Mercer of Aldie (d. 1671) and thence by descent

Jewel Office records of warrants to the Master of the Jewel Office, Public Record Office, LC5/107, p. 119. (dish)

'Dutchman', in the Goldsmiths'' Company records 1669, date of death unknown.