Thanks to Mike we know that George Ewings was almost certainly related to Isabella Elizabeth Maxwell (nee) Ewings, the [supposed] wife of John Maxwell , who he replaced at 10 Brook Street after Maxwell's death in 1796.
He may be the George Ewings christened 1747 at St Giles, Camberwell, the son of Richard and Elizabeth Ewings, and hence the sister of Isabella Elizabeth Maxwell.
23 January 1797
George Ewings entered a mark as bucklemaker at 10, Brook Street, Holborn. His first recorded mark
Moved to 27, Rosamon Row, Clerkenwell by 4 April 1803 and to 9, Ratcliff Row, City Road by 30 August 1804
Grimwade (page 505) speculates that George Davis Ewings, of 14 Yardley Road ,Clerkenwell may be his son.