Her article in thepeerage is here. If thepeerage is correct, her last name is Sturt, not Stuart.
From the Christie's Web site; spots removed throughout image, but especially along the left edge and part of the right edge, with Photoshop and shadows filled in to bring out details of the bodice.
Charlotte Sturt's coiffure has a bun rather than an assemblage of knots as well as bunches of sausage curls dangling from the sides.
Keywords: 1834, Carpenter, Cahrlotte Penelope Sturt, Brudenell family, Sturt family, British, neo-hurluberlu coiffure, bun, chemise, modesty piece, off shoulder vee neckline, pleated bodice, long puffed sleeves, lace back-flared cuffs, vee waistline, full skirt, brooch, wrap