Thank you to you all for these posts - I'm humbled by your knowledge, gentlemen.
Absolutely fantastic to find out something about it. The scope and tripod came from an old gentleman who had served as a sniper in the Seaforths during the war he told me he'd been issued the tripod with the telescope but I couldn't see how a silvery tripod could ever have made sense in the field - there's absolutely no evidence that this was ever painted.
Sadly he's no longer with us to ask - as with so many of our veterans - so all answers are gratefully received.
Paul