By Mollie Quirk Prince Harry appeared to endure a rather awkward interaction with a fan during his trip to London this week, with the Duke left red-faced by the run-in. The Duke of Sussex has been back in his former country of residence this week for the 10th anniversary of the Invictus Games. Last night, after a thanksgiving service for the games at St Paul’s Cathedral in the city, the father-of-two was on an impromptu walkabout. Harry conversed with fans and greeted a group of onlookers who all had their phones out to take snaps of the Duke, with Harry enduring a rather awkward moment. As Ha…