THOMAS STEWART
Inverness and Elgin
Examples of the work and mark of Thomas Stewart:

TS - ELN
Born Thomas McGuirman, son of Donald McGuirman, farmer, near Inverness.
Apprenticed to Alexander Stewart, Inverness, in c.1798.
Apprenticeship completed on the 27th September 1805, at which date he appears to have taken his Master's name.
Relocated to London, presumably to gain experience, and married there to Mary Lockwood, the daughter of the Jeweller, Richard Lockwood, at St. Martin in the Fields, Westminster, on the 26th February 1812.  Thomas Stewart sets up business on his own account at Elgin in that same year.
Thomas Stewart remained in business at Elgin until 1827, when he departed the town apparently because of financial difficulties.
By 1829 he had relocated to Inverness, and probably worked as a journeyman until c.1835 when he likely restarts his business and is recorded in the records of the Inverness Hammerman.
Thomas Stewart died on the 3rd March 1856, the business then passed to Thomas's son, Richard Lockwood.
More information regarding Thomas Stewart can be found in: 
Provincial Silversmiths of Moray and Their Marks by G.P. Moss - 1994
Trev.