LONDON.- Christie’s London announced the discovery of a rare portrait of Sir Alfred James Munnings Reading, circa 1910, by Harold Knight, R.A. (estimate: £30,000-50,000) which will be offered in the sale of Victorian & British Impressionist Art Including Drawings & Watercolours on Wednesday 16 December 2009. During a detailed examination of a painting by Dame Laura Knight, R.A. (1877-1970), Carnaval, circa 1915, Christie’s Specialist Tom Rooth noted that the back of the canvas was unusual; there appeared to be the edge of not one but two stretched canvases. In the process of skillfully removing all 83 nails which firmly pinned down Laura Knight’s canvas, Rooth first glimpsed a flash