Mark Wigglesworth’s often remarkable Prom with the BBC Philharmonic marked, in part, the 50th anniversary of the Royal Northern College of Music. The players, many of them alumni, were joined on the platform by some of today’s students. Stephen Hough, the soloist in Rachmaninov’s First Piano Concerto, was a student there, meanwhile, as was composer Grace-Evangeline Mason, whose Ablaze the Moon, given its world premiere, opened the evening.