OK...here is info from a little more research.
T R & S = Thomas Ross & sons Glasgow Scotland
Business was sold in 1903.
http://www.edinburgh-gazette.co.uk/issues/11561/pages/1082/page.pdf
Appears they mostly made electroplated. Go down to individualied letters |T| |R| & |S| which would match your makers mark.
BRITISH ELECTROPLATED SILVER - ALPHABETICAL LISTING OF MAKER'S MARKS: TA-UZ
Most of these electroplate and silverplate makers operated in the town of Sheffield from c. 1840 to c. 1940 (makers operating in other towns, e.g. Birmingham, are expressly indicated)
For an easier reference to the mark you are searching for, the alphabetical order relates to hallmark's letters or to 'figural' definition (NOT to firm's name)
|A|B|C|D| : the letters ABCD are inside separated square outlines
| ABCD | : the letters are inside a unique rectangular outline
(A)(B)(C)(D) : the letters are inside separate circular or oval outlines
( ABCD ) : the letters are inside an unique outline (of various shape)
[ ABCD ] : the letters are inside a shield
hand, tower, crown, etc.: describes (when possible) a symbol present on the hallmark
gothic : the letters are in gothic style
date indicates approximate period of firm's activity
http://www.silvercollection.it/SILVERPLATEHALLMARKSTZ.html