Thanks John. A Hurricane blade was my gut instinct – interesting to hear someone else with more knowledge also coming to this conclusion. This would also fit with its origins – 6 OTU and 56 OTU squadrons were based at Sutton Bridge from Mar 1940 through Mar 1942 and used the Hurricane Mk1 (as well as Lysanders, Typhoons and Spitfires). Active squadrons 254, 264 and 266 were also based there, flying a mixture of Blenheims, Beaufighters, Mosquitos, Battles and Spitfires.

Blimey, that was a quick reply! Have hopefully attached two pics. You can see at some point, someone painted the blade green – part of a fence??