You already mentioned Popski's Private Army, but the chap who created the unit Major Vladimir Peniakoff, MC is worth mentioning. Initially a concentious objecter in WWI but eventual served in the French Artillery in WWI as a private because he didnt want to waste his time training as an officer in the british army.
Next Herbert "Blondie" Hasler leader of the Cockleshell Heroes in the Operation Frankton raid against German ships harboured in Bordeaux. Haslers theories and practice where later to be used by the SBS. He was put forward for a VC but it wasnt granted. Hasler after the war went on to invent the Hasler Self Steering Gear for yachts that allowed single handed sail across large expanses of see. He also instituted the Observer Single Handed Transatlantic Race which he aslo raced in. He came 2nd to Sir Francis Chichester.
Third and sort of communications related on Thomas "Darkie" Waters a corporal in the Royal Crops of Signals. Waters was a wireless and line operator (though the old linemen(aka "lineys") of theSignals used to clain he was one of theirs) Waters was attached to 5 Para Brigade for the raid on Peagus Bridge in Caen. During the attack on the bridge Cpl Waters rescued a wounded comrade. Repaired a communications line multiple time under fire. He was awarded a MM. Water was later wounded trying to protect other soldier during a training excerise when a pin was pulled from a grenade. He Lost an eye and had a metal plate fitted to his head. Almost every Sergents mess in the Royal Corps of Signals has a copy of the painting by Peter Archer of Corporal Waters legging it across Pegasus bridge with reel of D8 line to repair another cut line. His example is used by the Signals to emphasise "comms must get through no matter what