Can Anyone Identify The White Boat Hull At The Extreme Top End Of The Harbour?

A Memory of Polperro.

Going through some old photos with my partner recently, I found two family photos, taken in the early 50s (no exact date) of Lansallos Street and 'The Fish Quay' and in the photos (taken on a 'Brownie' no doubt!), there was the hull of what I believe to be an ex-WW2 'British Power Boat Company', Motor Gun Boat or Motor Torpedo Boat (or possibly an ex-RAF Air/Sea Rescue Boat) afloat in the harbour. It seemed to be moored behind 'The Jew's House' near The Fish Quay and a shop named 'Sutton & Martin' (or something similar...the first two letters are not clear). It was simply the hull with no or very little superstructure, just some timber stored on the deck. It would have been approx. 68'-70' long.
Does anybody have any idea of the name/number or what happened to the hull.......she probably ended up as a houseboat somewhere nearby? It would have stood out as one of the largest hulls in the harbour!

The white hull in the Frith photo certainly looks very much like the hull of an M.G.B!
Any information would be gratefully received. Tim Deacon/Southampton.