If, say, Englishman kept his head … (4)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

POM (Englishman) round E[nglishman] for the Kipling poem (quoted in the inscription above the players’ entrance to Wimbledon Centre Court: “If you can meet with Triumph and Disaster And treat those two impostors just the same …”) My top favourite clue