Danny 42C:-
The solution was an enamel mug. I was issued with one, it clattered a bit when carried with your "irons", but it was virtually indescructible.
I too, as a CCF cadet at summer camp, was so equipped. Being keen to do everything according to the book, we marched to the airmen's mess holding it and the irons in the left hand held in the small of the back, while swinging the right arm as per normal.
When we had consumed our vittles, the plates were scraped off into the swill bins and stacked for the staff to feed into the dishwasher, while our personal implements were rinsed off in a trough of superheated water (well so it seemed), shaken, returned to the left hand and small of the back for the return march to the billet. Oh how proud of us our Mums would have been!