When you refer to "commandos" you are referring to Brittish forces developed during WWII. I believe they used both Sykes and Fairbairn to develop their commando hand-to-hand combat methods and training. Sykes and Fairbairn had worked for the Brittish police force in Shanghai before the war. It was an awfully dangerous place and they worked on developing hand-to-hand techniques that borrowed from various European and Asian fighting styles. They also made some double-edged daggers and worked on knife fighting. By the way at least one US marine stationed in Shanghai was involved in the work.
The Brittish made several models of the commando dagger. The first has an S-curved cross guard, an intermediate model had a cast grip with beads-and-ridges, later models I think had ribs or checkering. The US Marines made a model with a checkered metal grip.
The commando dagger is very thin by current standards and points were often broken. They have a great history and mistique. I've got one of the beads-and-ridges models that I prize highly.