Well I waited and played for time and lo and behold ebay came up trumps - and with the chrome with black ring bezel variety so I've ordered the whole unit which will be less faff than swapping the glass (I hope!) - I would have gone for any unit just to salvage the glass originally but I lucked out!
The seller also has the NS unit so if you're interested (ITSv40)? I'm not sure how long my V40 will live on for but I was planning to offer mine up to you in the future if it came to it as you've always been very helpful
however if you go for the NS one on ebay, I'll happily offer my OS with the broken glass and you could swap it over?
https://www.ebay.co.uk/itm/394259322...cAAOSwZCljMVnx