By Joseph Wilkes & Rebecca Russell Prince William and Kate Middleton have neither the “will or the strength” to “deal with ‘the Prince Harry problem’,” a royal expert has said, as the younger Prince makes his long-awaited trip back to the UK. Top royal commentator and former BBC royal editor Jennie Bond claims the “boot is on the other foot” following the Princess of Wales’ cancer diagnosis. Not only do Harry’s previously aired grievances that sparked a rift with the royal family now seem “utterly trivial” by comparison, William and Kate’s “frightening fight” means the future King and Queen ar…