22.12.1788 see John Walker.
J Walker was in Godwin's 1796 list near the end of 1788, crossed out, and in 1794 version as John Walker.
Since Godwin saw him after dining at George Robinson's this may well have been Robinson's brother-in-law 'the book-auctioneer of the trade' mentioned in the DNB article on the Robinson family of booksellers. But John Walker was a very common name.
17.7.1795 at Amelia Alderson's, John Walker & Capt Hamilton / 17.7.1805 John Walker at Joseph Johnson's / 27.11.1805 J Walker there, see Walker
11.1.1809 call on Clark (…