William Turner is listed in ‘The London Book Trades’, Ian Maxted (Dawson, 1977) as a print-seller, frame maker, carver and guilder of the late 18th century. His silhouette work, recorded in ‘The History of Silhouettes’ by Jackson, is in fact a print of a painted silhouette of Queen Charlotte published in 1782. The print bears his signature but it is unclear whether the original silhouette was painted by William Turner, or indeed if he produced any silhouettes himself.
Source: McKechnie (Author of, British Silhouette Artists and their Work 1760-1860)
Turner, William (McKechnie Section 2)