Her article in thepeerage is here.
From the Athenaeum.
This is a super-glamorous version of British casual with Lady Louise moved indoors wearing a gold waist band, cuff bands, and neckline ornament as well as gold figures in her over-skirt. Her dress is in keeping with that worn by Lady Sunderland in 1786 or Lady Cecil Rice in 1762.
Keywords: Kauffmann, Louise Henrietta Campbell, Baroness Abinger, Campbell family, Scarlett family, Baroness, British, high straight coiffure, ribbon headdress, veil, under-bodice, vee neckline, modesty piece, over-bodice, scoop décolletage, elbow length puffed over-sleeves, long tapered under-sleeves, cuffs, waist band, close skirt, under-skirt