SYDNEY, NSW: DAVID FROST, ARRIVED IN SYDNEY TODAY, PREDICTING HIS FORTHCOMING INTERVIEWS WITH EX PRESIDENT NIXON WOULD BE THE MOST CHALLENGING WORK HE'S EVER DONE. MR. FROST SAID THE INTERVIEWS DEALING WITH MR. NIXON'S TERM IN OFFICE AND THE WATERGATE BREAK IN, WOULD MAKE A GENUINE CONTRIBUTION TO HISTORY.