J.K. Rowling brought back many a memory on Twitter when she reminded Harry Potter fans that today would be the first day of school for Harry’s oldest son, James Sirius Potter. School, of course, means Hogwarts School of Witchcraft and Wizardry. And as we well know, Hogwarts is no ordinary school. I'm in Edinburgh, so could somebody at King's Cross wish James S Potter good luck for me?