Billy Vunipola and Taulupe Faletau’s paths cross again on grandest stage yet

England’s Vunipola and Wales’s Faletau, whose remarkable backstories – from Tonga via childhoods together in south Wales – are intertwined, meet on Saturday as the standout No8s in the Six NationsWhen Billy Vunipola was just 11 years old he had it all figured out. “When I grow up, if I’m good I’ll play for Wales, if I’m very good I’ll play for Australia and if I’m not so good I’ll play for Tonga.” Twelve years on and his former Under-11s coach Dawson Jones does not let him forget it, nor the last line of a letter he received when the Vunipolas moved from Pontypool to Bristol in 2004. “I promis…