At the time of writing, the Cheltenham Festival is less than three weeks away and the feature race on Day One, the Champion Hurdle, seems increasing likely to involve a set-to between, or among, leading trainers Willie Mullins, Nicky Henderson and Gordon Elliott. Of course, Henderson is responsible for the defending champion, and favourite, Buveir D’Air, who seeks to emulate Hatton’s Grace, Sir Ken, Persian War, See You…