We rattled out of Dete Station towards the north-eastern boundary of Zimbabwe's Hwange National Park, an eager dozen – nine tourists, two engineers and one safari guide – en route from Victoria Falls to the Ngamo Plains, an elephant-laden grassland where dwindling acacia forests meet the arid sprawl of the Kalahari sands. I squinted into the midday sun and sipped a gin and tonic, balancing on one foot and leaning out of the side of our purpose-built, private railcar, hoping for a better ...