England’s George Kruis and Mako Vunipola set to return before World Cup

• Injured pair should be fit for August warm-up games• Brad Fields faces fitness race while Alex Dombrandt impressesEngland are optimistic the key Saracens duo George Kruis and Mako Vunipola will be fit to play a part in their World Cup preparations but Brad Shields is facing a race to be ready for the tournament.Shields returned home from the World Cup training camp in Treviso last week with a foot injury and his hopes of playing in the warm-up games before England depart for Japan appear unlikely. John Mitchell, the England defence coach, described Shields’s ligament tear in the lower-foot a…