His address was actually 17 Gt. Russell St, Covent Garden but this token is an example of a rare error address as reported in a sale of a similar example by DNW 13 Mar 2002. Webster was active as a successful coin and medal dealer from 1851-1885 and this token likely dates from this period.
It is noted by Forrer that he issued a token in brass that was produced by William Joseph Taylor (1802-1885) cf. http://sculpture.gla.ac.uk/view/person.php?id=msib4_1239728552
William Webster 1821-1885
The Numismatic Chronicle 1885