During a local vintage steam rally I was shown this photo of a Saunders-Roe Dark Class FPB model that was seen in Crete.
It shows a basic model that I believe was made to demontrate the various armament options that could be readily interchanged.
The photo was titled: "In the Maritime Museum in Chania, Crete. Fast Patrol Boat donated by Saunders Roe, Anglesey".
The question is, where did the penant number P21 come from? It doesn't tally with any RNCF, Finnish , Burmese or Japanese Dark Class that I'm aware of.