By Dave Burke The former boss at ex-National Lottery operator Camelot has been appointed to lead scandal-plagued Post Office. Nigel Railton will take over as chairman, replacing sacked Henry Staunton, who has been locked in an ugly war-of-words with Business Secretary Kemi Badenoch. Ms Badenoch selected Mr Railton following Mr Staunton’s sudden departure in January. The businessman admitted he is taking over at an “incredibly challenging time” for the state owned business, which faces a wave of public anger over the Horizon IT scandal. Hundreds of postmasters were wrongly convicted after fault…