Her article in thepeerage is here.
From the Bonhams Web site.
This charming portrait probably dates to about the time of her marriage to Arthur Chichester in 1761. Her dress is simple; her standing is betrayed by her satin dress and the pearls in her hair.
Keywords: 1761, Coates, Anne Hamilton, Countess of Donegall, Hamilton family, Chichester family, Countess, British, straight coiffure, jeweled feathered coiffure, veil, scoop neckline, modesty piece, close sleeves, floral bodice ornament, necklace, earrings, wrap