Antique Sheffield Plate tea service by Roberts Cadman Co. or successor

Antique 3 piece Sheffield plate tea set with coffee pot, tea pot, sugar; the creamer is not marked and does not match the rest of the set - it is included in this listing but unrelated.  The coffee pot, teapot (with bone detail on handle), and sugar all bear the bell hallmark first used in the 1780s by Roberts, Cadman, & Co.; this mark was also used by their successors through the 1890s.  The creamer is included in this listing but is NOT marked and does not match the rest of the set.  There are also some faint incised numbers and names on the bottoms of the 3 hallmarked pieces "Stones", "Brown" in appearance, and other various numbers.  The coffee pot measures about 11.25" tall to top finial on lid; creamer is about 5-1/8" tall to tallest point at handle; sugar is just over 4-5/8" tall to tallest point at handles; teapot is about 6.25" tall to tallest point at handle.  Imperfect, antique, pre-owned, used condition - there is some tarnish to the surface of all pieces and some scratching.  There appears to be a repair to the lid of the teapot - see beneath lid on underside.  Discoloration and scratching to the plating on the inside of the pieces (please see photos).