By his marriage in 1781 to Theophila, a niece of Sir Joshua Reynolds, Gwatkin became closely involved with the Reynolds family, and was chief mourner in 1792 at the funeral for Sir Joshua.
By his marriage in 1781 to Theophila, a niece of Sir Joshua Reynolds, Gwatkin became closely involved with the Reynolds family; his mother knew Frances Reynolds by the 1770s. He was chief mourner in 1792 at the funeral for Sir Joshua.