Her article in thepeerage is here. Lady Louisa Barbara was John Rolle's second wife.
From artuk.org. Also posted to the Revolutionary, Napoléonic, and Romantic Era Album here.
Lady Louisa wears a dress with an off-floor full skirt and full sleeves suggesting the early 1830s.
Keywords: Robertson, Lawrence, Louisa Barbara Rolle, Lady Rolle, Trefusis family, Rolle family, British, curly coiffure, tiara, coronet, lace neckline ruff, elbow length puffed sleeves, maxi-length full skirt, shoes