Not what you are looking for, however you can follow his career 1760-1770 on London Lives 1690-1810 website.
His employee number was 1329 and was appointed in 1733. His employment salary is listed from 1760-1770
In 1760 he made 190 pounds per year.
1762 it was 300 pounds and by 1767 he made 350 plus a bonus of 200.
The last entry 1770 he made 500 pounds plus another 500.
For the 1700's he did very well.
He wrote a will 16 January 1771 proved 22 January 1771 (PCC wills) on ancestry he left everything to his wife Ann.
A Susanna Whitehead and Richard Roberts testified to his handwriting.
My assumption Susanna is related to his wife Ann Whitehead whom he married by license 21 September 1756 at St Pancras