I was involved in some of the twilight shooting trials using the double aperture L1A1 sights in 1968. Ideally the LARGE rearsight aperture was used with a quarter rotatable foresight blade that contained a tritium vail that acted as a luminous foresight. It was during a series of Company shoots at Ashan ranges at figure 11 man targets (supposed to represent hoard attacks by advancing VC). I think the results were abysmal but better than the normal sights. The big Whites/International and Bedford trucks taking us all to and from the firing points weren't using headlight to preserve our natural night vision and one of the trucks ran over a whole line of standard rifles from C Company smashing them to shreds. It was just one of those accident losses during training on active service and that was that. But, the sight, later known as the HYTHE sight was kept until we got some US night vision.

That's the end of the history lesson chaps...........