Curiosity still grips the finder. He plans a second visit in order to photograph the unit more comprehensively, this time including various numbers and letters printed on the casing.
We also came to the conclusion that it had not been fired, due to the lack of scorching around the nozzels, however there was signs of soot and blackening at the rear where the cover had been removed, which may have indicated a faulty unit (or that some Ned was trying to set fire to it) !!
You say that the blue nozzels are an indicator that it was a dummy, but it was packed with components and was pretty heavy, also other pictures show this type of unit to have blue nozzels, perhaps they were also dummies.
Had it been a trophy, it is still hard to understand how it made its way deep into the Cheviots.
Thanks for the info guys, any more would be welcome !