What is it about the Carnethy 5?

The field lies open and exposed, looking up to Scald Law and Carnethy, the highest points of the brown and grey Pentland Hills. Above a saturated bog is a hummock of low grass, decorated by clumps of scruffy gorse. Runners cower in the vegetation, squatting on ground littered with sheep droppings, pinning numbers on vests,…