Born c 1755.
Died 1821.
Although no website reference to a date of birth has been traced the London Deaths and Burials Index 1813-1980 for a burial recorded at St Bartholomew the Great dated 28th October 1821 of William Burwash aged 66 years is probably a reference to the watch pendant maker referred to in Grimwade's book.
BURWASH, William (Grimwade p.455)
Moderators: MCB, buckler, silverly
Re: BURWASH, William (Grimwade p.455)
Wrongly recorded as William PURWASH, a silversmith etc., of 14, Bartholomew Close, Little Britain.
Source: Johnstone's London Commercial Guide - Corrected to 31st August 1817 - Andrew Johnstone - 1818
Source: Johnstone's London Commercial Guide - Corrected to 31st August 1817 - Andrew Johnstone - 1818