Okay this is honestly a really minor thing but it's been bugging me when I read RWRB fics
Prince of Wales is the title given to the male heir apparent of the British monarchy
The children of the heir apparent are Prince/Princess xxx of Wales
To use a real-life example real quick, the children of Prince William and Kate Middleton are Prince George, Princess Charlotte, and Prince Louis of Wales, but the Prince of Wales is William. Before that, the kids were Prince George, Princess Charlotte, and Prince Louis of Cambridge because William's primary title was Duke of Cambridge
In the book, Henry is Prince Henry of Wales, but he is not the Prince of Wales. His mother Catherine is the Princess of Wales, and when she is queen Philip will be the Prince of Wales. (Even that's not entirely accurate because there isn't a designated title for a female heir apparent, and Princess of Wales is for the wife of the Prince of Wales, I'm guessing because before 2011 older sisters ranked lower than their younger brothers in the line of succession)
So the movie changing Catherine to Duchess of Edinburgh and Philip to Duke of Cambridge actually is closer to reality, in that case, Movie Henry's full title should be HRH Prince Henry of Edinburgh
Which is kinda nice since Nick's acting career started with him doing a version of Spring Awakening in the Edinburgh Fringe Festival
Yeah again it's a minor thing but I'm a nerd about this stuff so yeah