It is not the politicians that need replacing it is the system
Our politicians (both sides) have systematically built a wall around the political system and given themselves total power so that in effect we have a dictatorship, and the big two continue the fight by doing all they can to restrict and remove any independents or minor parties
There is at the moment no system to force a politician to explain their actions to the voters. Our politicians can literally do anything, spend anything, bring in any laws that they want to do without any fear of reprisal