After 1883 a Numerical mark was used in the following form:
Rd 742833 or Rd No. 742833
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1903 403200
1904 424400
That mark is listed as "unidentified" at this site:
BRITISH ELECTROPLATED SILVER - ALPHABETICAL LISTING OF MAKER'S MARKS: FA-FZ 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)