A nice pinky-sand coloured Brit SF-used Compo which certainly looks like one from the National Plastics stable (no label). This one clearly had visor brackets on at one stage (see the blue model) but the liners differ in that the blue one’s liner can be pulled out amid some stiff Velcro defence but this one (which is Mk6A-esque) is pegged in by the tell-tale NP rubber darts.

The one on "CompoSite" (plug plug) has similar darts Composite Helmet, Ballistic helmets, Military helmets UNITED KINGDOM, UK HELMETS, BRITISH helmet, Kevlar helmet

So, whatever it’s model number, and lets stick with 600 / 575 for now, there was clearly more than one model…like several other NP models….one with a pull-out liner and one more robust.

Perhaps non-military = no darts and military = darts?

…anyway, a nice "been there" lid…….which should attract about 2 responses!

Click to enlarge the picture