The Secretary of State may by an order under paragraph F1 1, 3 or 3A above, or by an order under the said F2section 2 relating to a united district consisting of the whole or part of a National Park, or by an order under this paragraph, confer on a joint or special planning board for a National Park or any part of a National Park any of the additional countryside functions as respects the Park or, as the case may be, any part of it.