Blimey some memories there ! In Germany 1979-1990 we were still eating from those tin cans on exercise. The hay box had been replaced by an ali box known as a hot lock which had a piece of smouldering charcoal in a little receptacle.
The lad scratching his ear is wearing a detachable collar shirt had he polished his studs ?? . At a guess the truck would be a Bedford RL with a box boy originally concieved for RVT applications. The attached are borrowed from another site and show a gang of plumbers on a big BD task on the Yorkshire Moors, I presume the one next to the water trailer is their diner,