Formally
The Queen must always be greeted formally as Your Majesty or Ma’am. But, the Royal Family let things slide for the grandchildren, allowing them to use their own affectionate names in private.

Formally
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The Queen must always be greeted formally as Your Majesty or Ma’am. But, the Royal Family let things slide for the grandchildren, allowing them to use their own affectionate names in private.

Formally