See Castle Street East 1 to 15 &c in London Addresses dataset.
Castle St East Land Tax No 4 1791-1798 Catherine Brown No 6 1796 Catherine Brown for tenants No 7 1791-1799 Catherine Brown (for tenants 1796 Catherine Edmonds for tenants 1797) / Sun Fire 1790 Catherine Brown widow Nos 4 & 7 / Sun Fire 1794 Catherine Brown widow Nos 4 & 7
William Brown (his mark) wid = 13.11.1786 St Marylebone Catherine Dowling (her mark) sp / 1.9.1798 Middlesex Sessions Rex v Mary Wragg for a nuisance, bail Thomas Hall coachmaker 23 Cleveland St St Marylebone and Catherine Brown widow 4 Castle St Oxford Market (Mary Wragg Land Tax 1789-1794 14 Gresse St St Pancras SunFire 1793 Mary Wragg widow 12 and 14 Gresse St Harris's List 1793 12 Gresse St Miss Towns-d parlour Miss Char-ton 1st floor)
No 4 was in Harris's List 1788 (Mrs H-ll-ngb-rg) and 1789 (Mrs C-p-r). See Brown, Edward (of No 6) and Brown, Elizabeth, and Edmonds Thomas (of No 8 where miss Br-wn was in Harris's List 1788) and see Morgan, Mary of No 6 1797-8