straight to your inboxRio Ferdinand believes that Manchester United need to let David De Gea know that he faces competition for his spot in the team after a poor end to the season.De Gea has come in for some heavy criticism in recent weeks after making several high-profile errors that proved costly for United, most notably against Chelsea in the FA Cup semi-final.As a result there have been growing calls for Dean Henderson to be given an opportunity as the club's new No.1, after the 23-year-old