By Tom Blow Erik ten Hag has described Jadon Sancho’s spell at Manchester United as “not a success” after the winger’s temporary exit. Sancho, 23, rejoined Borussia Dortmund on loan until the end of the season on Thursday. The England international was dropped from Ten Hag’s squad in September after falling out with the United boss in public and hasn’t played for his parent club since. Sancho made his comeback in Dortmund’s 3-0 Bundesliga win at Darmstadt on Saturday, as he came off the bench to assist a late Marco Reus goal. Ten Hag was asked about Sancho’s exit ahead of United’s game against…