All About Pocket Knives

Anyone know the history of these? I recently picked this up up, WWII? I can’t find out much about them on line.

A lot of the British cutlers seem to have made knives with copies of or blades similar to the Fairbairn-Sykes commando knives. I have a J. Nowill and sons version very much like yours. I've seen them with the stacked leather handles, bone and also stag grips. I believe some were made during the war as well as post war.