Ozzieman - No worries. Yep, like what Mike said. That is the long range front volley sight, calibrated for the .303 Mark VII round, from 1700 yards onwards to a good 2600 yards. It's a very rare thing to have the originals, so if you have that and the rear volley sight which is just over the left side as well, but beside the rear sight, then it makes that particular P-14 very appealing to the collector.
I don't have them on the P-14s I have, they were removed (rather crudely at one point) because, it was found after the hard-won experience of WWI that volley sights were about next to useless, served very little purpose, so the unit armourers were often asked to remove them where possible. They can be restored though, via a mob in the UK, but the threads used aren't of the normal variety, they're unique "Enfield" threads, so it'll be a real interesting time when I get around to fixing them!