Hi Suzie,

Look in my book on pp.232-234, and you will see many marks and a lot of information regarding R H & S L Plant (Ltd.) at Tuscan Works, Longton, Staffordshire. Tuscan China was their trade mark, and it is a crown with a pair of wings as you described. The ad from the Pottery Gazette on p. 234 shows their mark and Tuscan China trade name at the top of the ad. You will see two different cups and saucers (standard willow and Mandarin pattern) as well as a plate and a teapot -- all bone china.