On the first scene, where the cockpit of the plane is seen, all the instruments show red flags. This small flags are used on analog instrumentation to show that the instrument is inoperative. As all the instrument are inoperative is clear that avionics are turned off, and this scene was shoot on a non powered aircraft.
Charles confronts the Queen about being sent away and repeatedly refers to his being given a 'posting'. Posting is an Army term, the Royal Navy have 'Appointments' for their officers, Charles should have said he'd been reappointed or been given a new appointment.
Arthur Scargill is shown negotiating with Prime Minister Ted Heath, but he was not part of the NUM leadership in either the 1972 or 1974 strike. The NUM President was Joe Gormley. The main radical in the media spotlight was NUM Vice-President Mick McGahey.
When Lord Mountbatten goes to visit Prince Charles in 'Dartmouth' the location is actually the Royal Navy College at Greenwich several hundred miles from Dartmouth.
Princess Anne should not be wearing a tiara at the anniversary dinner, wearing a tiara is reserved only for brides on their wedding day and married women.