 PRINCE CHaRLES has been accused of hiding behind stringent new Freedom of Information restrictions to conceal lobbying of the Government for changes to policy after it was revealed that he met at least eight ministers in a 10-month period.  Campaigners called for an urgent review of changes to the Freedom of Information act ushered in during the final days of the last Labour government which granted the heir to the throne - who is obliged to be politically neutral - an absolute exemption from the release of details about his contacts with ministers and senior civil servants.  The amendments mean that the prince, who has been accused of exceeding his constitutional powers - notably last year when he intervened to halt a ?3bn property development by the Qatari royal family - is no longer the subject of a public interest test to decide whether the content of his communications with the Government should be published.  Suspicions that Prince Charles is straying into political territory were increased yesterday with the revelation that he had held nine private meetings with ministers, including the Chancellor, George Osborne, the Education Secretary, Michael Gove, and the Environment Secretary, Caroline Spelman 