Martin Lewis has warned hundreds of thousands of people are in the wrong tax band, and they could be owed thousands back in overpaid council tax. The money saving expert, who has been campaigning about the issue since 2007, said 400,000 are estimated to be in the wrong council tax band. Speaking on BBC Radio 5Live’s The Martin Lewis Podcast, he said: “Everybody should check their council tax band and if it’s wrong, you should challenge it.” The financial journalist explained there are two checks he suggests people make. He said: “Check number one – the one that matters most – is what I call th…