Her article in thepeerage adds she was the daughter of Christiana Riccard. While her birth date is unknown, she had younger siblings born in 1662 and 1663. The Kniller (Kneller) brothers arrived in England in 1674. Kneller's Wikipedia article states, "He founded a studio which churned out portraits on an almost industrial scale, relying on a brief sketch of the face with details added to a formulaic model."
From bbc.co; spots removed from background with Photoshop by gogm.
Lady Cullum's dress reveals a great deal of her plain chemise with the draw string showing prominently.
Keywords: Munro - Olive, Kneller, Anne Cullum, Berkeley of Stratton family, Cullum family, British, straight coiffure, chemise, scoop neckline, ruffles, elbow length puffed sleeves