According to her article in thepeerage, Joyce Crowther married Sir James Winter Lake in 1764.
From bada.org/object/joyce-crowther-lady-lake-1744-1834-diana-francis-cotes-ra-1726-1770-painted-c1767. Also posted to the Reign of Louis XV - 1715 to 1774 Album.
Here is British causl mixed with strong overtones of luxe with the keweled belt and clasps and decorated bow to play Diana.
Keywords: 1770, Cotes, Joyce Crowther, Lady Lake, Crowther family, Lake family, long straight coiffure, hair jewelry, chemise, scoop neckline, three quarter length puffed sleeves, criss-cross bodice, vee décolletage, quarter length notched puffed sleeves, clasps, jeweled belt, close skirt, theatrical dress