Thank you to everyone who has contributed to this thread. It seems as though the Wellington is the odds on favourite at the moment! I have heard that there is one (the only existing one I believe) at Brooklands so maybe a visit there would solve the mystery. As (at least) one crashed such a short distance away it could have been a memento someone picked up and thought it would be a laugh to attach it to their tractor !?! so ending up in ‘my’ field. Guess we will never know for sure.

No part number I’m afraid. In answer to NickB it was between Frilsham and Bucklebury. Do you know that area well?
So, we are down to a Wellington or a Liberator. Thats brilliant I just need to gen up on these so I know what we are looking at.
That is indeed the same diagram albeit in a tad better condition than mine! Nice one.
Thanks everyone and any more suggestions or info very welcome.