Paul Gustard’s move to Harlequins may hurt England’s World Cup preparations

• Gustard to coach Harlequins after England’s South Africa tour• Injury to Wasps’ Jack Willis adds to Jones’s back-row problemsEngland’s World Cup preparations have been thrown into turmoil with their defence coach, Paul Gustard, leaving Eddie Jones’s coaching staff to become Harlequins’ head of rugby. It is believed Gustard – the current England defence coach – will see out his duties on next month’s tour of South Africa before vacating his role as one of Jones’s key assistants only 15 months before the World Cup.The appointment will be officially announced on Monday by Harlequins, who have r…