Indeed. In your original post of this photo (post #4), it appears the other communications specialist (only partially in view, to the left of the one you're pointing to above) is using an Enigma machine - something not often seen in period photos.

I've got a couple M90 helmets with decent liners, but I'm going to leave it as he brought it home...ditto for the ziggy-zaggy.  When I personally owned one of these helmets circa 2004, it was missing the badge and the guys making the repops were doing a brisk business in them, but I haven't seen those in years.   Mark sends

Thanks! I suppose this could be close to 35 years old if it was his cap in the early 90s. 

Is it an issued item? 

Hi Dammen026,   I believe what you have is a squadron lapel badge.  It is not a souvenir.

Matt, I think you've found your man!  The key to the age of your cap lies with when he was promoted to Group Captain.

…..and here is another taken at the museum, looks like your one.  so looks as tho there was a couple different types. Interesting🤔🧐  

Unknown unit, France 1940, a half track of the higher command type though.

I was in Normandy a few weeks ago and snapped a pic of some airborne stuff from the ‘Pegasus bridge ‘ museum.  The tab is different I see. 🤷‍♂️maybe glider pilot tab, I can’t remember now. But interesting  

Wow, I'm impressed! I will get a better scanned image when my friend returns. Many thanks.

Where to start? For sure a WW I German staff map (classified "Geheim" - secret) showing German trenches and positions in the Hennemont area. I think in fact these are two maps glued together at the red line I have marked on your picture because of the unusual format and due to the different dates I have marked as well. The German term "besetzt" means manned (positions). "Nicht besetzt" is for un-manned/prepared positions. What we also see are areas of small arm (MG?) effective ranges. The red square "Planquadratteilung" could be used for encoding and decoding local informations. Defintely need to see more close-ups and the map description on the outer edges. I can´t see any entries of enemy forces, units etc. I will check my archive for German WW I tactical signs for more informations.    

This appears to be a private purchase KS98 dress sidearm.  It has two rivets in the stag grips and a rectangular drain in the grip next to the steel guard.  I think it is most likely late WWI or early Weimar Republic.   A nice private  purchase bayonet.