By John Dickie Sadiq Khan may have been reelected for a historic third term as mayor, but if he’s to get London firing on all cylinders we need more fiscal devolution, says John Dickie Londoners waking up to yet more train and tube strikes this week will hope the newly reelected mayor, Sadiq Khan, can use his new mandate to tackle the big challenges facing the city, including hugely disruptive industrial action that has blighted the capital for years. While transport is one area where the mayor has considerable control, Khan – like the nine other metro mayors elected across the country – has l…