‘If I can’t see a factory from up here,’ I mutter to myself, throwing the car round an uphill bend of the B5032 south of Ashbourne, ‘I must be in the wrong county.’ But no, I’m not lost; there below me is a long pale slab of a building that announces itself as JCB World Headquarters — adding, on a giant polythene wrap, ‘Celebrating 1,000,000 Machines May 2013’.