I have just spoken to StarlightNV in Manchester who have given me some extra details about the monocular.
Firstly it was built in 2009 and originally sold to somebody in Scotland.
Secondly, it is a D Grade and not a C Grade as I was told, so my apologies there to anybody there that is disappointed. This does not impair the performance of the scope at all and viewing ^distances between the various grades are negligible. As to the spot and specs on the tube, there is a couple of blemishes at 12 and a few tiny spots between one third and half way out from the centre but they have little or no impact on performance. I hope this clears things up because I have so many PMs I cannot answer them all in a timely fashion
Bought this a couple of months ago and took possession of it three weeks ago in anticipation of a change in Swiss law with regards to NV add ons. How wrong was I! I have used it once and it is a good monocular. I haven't tried it as an add on but it does come with an insert for a scope with an eye bell diameter of 39.75mm. It did not come with a datasheet. Looking for xxxx including postage. Regards Conor