By James Nation With think tankers and campaigners being appointed to government, it’s tempting to think these secretive groups are calling the tune, but there are better ways to work out what Labour really thinks, says James Nation Over the last 14 years, there was a theory some commentators that went something like this: yes, Conservative Prime Ministers might take decisions behind the black door of 10 Downing Street. But the real power and direction came from the network of think tanks behind ‘the other black door’ of 55 Tufton Street. With Labour now in power, you might ask whither the ‘Tu…