See Castle Street East 1 to 15 &c in London Addresses dataset
No 11 Castle Street East Land Tax 1791-1796 John Fletcher Land Tax 7 Markett Place (Oxford Market) 1800-1803 John Fletcher
Will PCC of John Fletcher of Little Castle St greengrocer dated 9.8.1787 wits Wm Cross cheesemonger Castle St (QV*), G Hartforth (QV*). His widow Sarah proved 18.2.1789 / burs St Marylebone John Fletcher (adult) 26.7.1788, 8.2.1789. The following are just possibles for JF or his possible son of same name. John Fletcher gent bach otp = 7.1.1763 St Andrew Holborn by lic Sarah Bayes sp otp / John Fletcher gent bach of St Anne Soho = 11.1.1780 St Giles i t Fields by lic Sarah Pickhaver wid otp. The will PCC of John Pickhaver goldworker of Gt St Andrew St dated 11.4.1779 widow Sarah proved 28.4.1779 but the JF she married was probably attorney of Litchfield St Soho / JF potato warehouse 76 Oxford St Bailey's 1784 / JF glover 37 Oxford St Bailey's 1785 Wakefield's 1790 / JF bach = 7.1.1796 St Marylebone by banns Sarah Mitchell sp (her mark) / JF otp = 19.2.1797 St Marylebone by banns Ann Leaney otp