‘Have a look at this,’ says Daniel Harding, goggle-eyed, between mouthfuls of salmon. The pictures on his smartphone show Claudio Abbado, one of his mentors, conducting the Berlin Philharmonic in Schumann’s Scenes from Faust, a work that gets closer to Harding’s musical personality than any other, which he has just recorded with the Bavarian Radio Symphony Orchestra, and which he will conduct in Berlin in December.