From the 1945 S Class Submarine (P256). Screen badges are rare as you know, only one was cast for each ship, but to find a submarine Screen Badges is extremely rare. From the Ferrers Walker Collection, ex National Museum of the Royal Navy. Solid cast bronze.

She was an S-class submarine of the third (or “third batch”) built for the Royal Navy during WWII.  She was laid down by Scotts at Greenock on 15 November 1943, launched on 27 July 1945, and commissioned after the war on 28 December 1945.  Her duties were peaceful—she took part in the 1953 Fleet Review for Queen Elizabeth II’s coronation.  She was sold for scrap on 28 February 1962 and broken up at Gillingham.