Lady Janet's article in thepeerage is here. See the caption for the next image for a biographical sketch. This may be an advertising portrait.
From Bonhams Web site.
Lady Fall is actually dressed in a casual manner in this 1747 de Nune portrait. The sack back of the robe à la française can be seen.
Keywords: 1747, de Nune, Janet Fall, Jenny Fall, Janet Anstruther, Lady Anstruther, Fall Family, Anstruther family, British, long curly coiffure, cap, chemise, trapezoidal neckline, lace, knotted bodice, facings, square neckline, stomacher, bows, elbow length close sleeves, cuffs, under-sleeves, robe à la française