Prince Phillip's recent passing rekindled my interest in this question. Why are there so many ways to address royalty? Your Highness. Your Majesty. In olden times, they just addressed (him) as Sire. Does that one still apply? And when I was still in grade school, I got a book on old Grimm's fairy tales. And in one story at least, the king was addressed as 'My Liege'. Do they all apply? Or do they come into play in different circumstances? Forgive me for wondering.
You'd think "Queen Elizabeth, Buckingham Palace, London" would be sufficient for the USPS.... Fortunately, addressing royalty is above my pay grade. Come to think of it, the most senior government official I interact with on a regular basis is my mail carrier.
On presentation to The Queen, the correct formal address is 'Your Majesty' and subsequently 'Ma'am,' pronounced with a short 'a,' as in 'jam'. For male members of the Royal Family the same rules apply, with the title used in the first instance being 'Your Royal Highness' and subsequently 'Sir'.
this kind of relates to what i find embarassing about humans and being one. i find the concepts of hierarchy conceptually embarassing, though i have no wish to offend or depress anyone who feels otherwise. protocalls do have their place, but i do wish everyone would offer each other that same elivated level of dignity and consideration for it. like the asian bow, but without the differing levels of degree. well of course i'm being more generalized then the subject. i'm just glad i don't have to live the way they do, the royals that is, with all the ostentation that to me is very anti-aesthetic and anti-creative.