Just over half a square mile in the centre of overcrowded London. One of the most unusual parks in the world. A place for eccentrics. A place for speakers and lovers, winter swimmers and yoga fanatics, brass bandsmen and amateur horsemen, children and dogs, policemen and pop protesters-and even ex-actresses exercising their pet ducks. A park which needs its own police station and has its own pets' cemetery. A royal park, where monarchs hunted wild -boar and gentlemen duelled. A report by one film crew, with one reporter, JOHN PITMAN , and one director, JENNY BARRACLOUGH , of one day in Hyde Park. It wasn't a day of demonstration or protest or pop concerts - nothing special about it. Except that, perhaps, any day in Hyde Park is special-if you're there.