In 1944 Harry was a conscript with the D Day invasion forces of the English Army. Harry did not like to talk much about the war, however, he did open up a little to his friend Baker-Moss (Mossy) who was in the RAAF when they met. 

Mossy writes:

I suspect that we first bonded as a consequence of the shared experiences surrounding service life – Me being serving in the RAAF at the time; and Harry and his brother Tony both WWII veterans. I believe Harry attained the rank of Sergeant during the war and was at one stage the radio operator assigned to accompany his Unit commander. I am not sure if you can picture the very old style large kind of army backpack radio, but that is the type that he carried across Europe following the invasions on D-Day.

In many instances Harry was the second most forward British Soldier in the front as it advanced towards the Germans – his CO being the most forward! I particularly recall his description of how he was required to throw himself to the ground “gently” so as not to put the radio set out of tune (the valves etc were very hard to calibrate and a sudden jolt might require hours of work to get a signal back to HQ). (Baker-Moss)

His close friend Wally Marek writes:

There are a lot of things about Harry that remind his friends of the genius of Spike Milligan; whereas Spike went to England we got Harry. Harry had the same capacity for not taking himself seriously. After Harry did his time fighting Hitler he became a London bus driver. As Harry told it, the life of soldiers rebuilding their lives after the war was extremely creative. (Wally Marek)

Harry was also intrigued by the language of Esperanto, so set about studying and mastering the language so well that he achieved the title of Professor in the language, he was quite disappointed when it did not take over the world as had been predicted.