GB QV 1840 SG3 1d Grey Black Plate 11 LG On Cover Rare cv £16000

A  super rare 4 margin Penny Black plate 11 (eleven) on Cover. Super Maltese Cross tying the stamp to the cover.  
Cover from Dorchester to Bristol dated 16th July 1841. A super and very rare addition for your collection of the rarest Plate on Cover. Highly desirable very attractive, and high SG cat value of £16000.