Here’s a really long shot – how about it being the prop from the Pobjoy R that originally powered the Spartan Clipper G-ACEG (the R was replaced with a Niagara in 1938)? That has the right geographical connections, having been built by Spartan at East Cowes in 1932. The aeroplane was destroyed in an air raid on Cowes in 1942. Against that possibility is that all the photographs that I’ve seen of G-ACEG shows it with a two bladed prop – but I can’t say whether those photographs show G-ACEG with a Pobjoy R or Niagara up front.