By John Cross Jadon Sancho gave Manchester United a taste of what they are missing after producing a brilliant Champions League performance. Sancho was sensational as he helped Borussia Dortmund produce another upset as they took a big step towards the final at Wembley on June 1. And his dazzling display must surely make the United hierarchy question why they could not get the best out of the £73m England international during his three years at Old Trafford. This was Sancho back to his impish best, dribbling and jinking down the wing as the industrial city of Dortmund upset the wealthy Parisia…