They look pretty similar lol, the OS is a little sleeker and more boring looking, and it makes it seem like there's a huge empty space under it because there's no lever to flick between 1-4x mag.
Doesn't help that a lot of the Brit Forces impressionists are just compromising and buying the DR for their L85 Afghan builds, even though they're wrong. Just helps circulate the incorrect info. I don't think many people actually realise that there are multiple different types of Elcan Spectre.
I'd love to know more about the micro red dots the OS models have fitted on them, I imagine they're still Docter sights, but the little case thing they're put in looks enormous.
I always thought it was funny they called it a Light Weight Day-sight, when light is the absolute last thing it is.