I was deeply anxious during the train journey from Vienna to Bratislava, the Slovak capital, in 2014. Holocaust survivor Tomi Reichental was expecting me there, together with Gerry Gregg’s film crew. They were shooting the documentary Close to Evil. Tomi was born in Czechoslovakia but moved to Ireland in 1959. He had been a young boy when he and his family were deported by the Nazis to the Bergen-Belsen concentration camp in Germany in 1944. Tomi survived, but 35 of his relatives were murdered in the Holocaust; his grandmother died before his eyes in the camp.My grandfather, however, was Hanns...