It will be for many, as for this writer, hard to credit that Frank Auerbach is now eighty-four years old. Born in Berlin in 1931, to a prosperous middle-class family, he came to London in 1939, as a child refugee from the brutality of the Nazis, who later killed both of his parents in a concentration camp. This year will see his major retrospective mounted at the Kunstmuseum in Bonn and later at the Tate Gallery in London. It will be the largest and most comprehensive showing of Auerbach’s work ever seen yet and it promises to provide telling insights…