Andrew is very far down the line and whomever is writing this complete and utter male bovine excrement is/are UNEDUCATED in the extreme AND bloody STUPID to boot!
I have been interested in European/Brit royal history since I was around 8 1/2 and read a book about the Royal houses of Europe and the UK from very early times forward.
I've also been an Anglophile all of my life and have read and own many shelves filled with books about this stuff.
What are you basing your assumption on?
In 1953 the Regency act was TEMPORARILY amended to allow Prince Philip to be regent displacing Margaret.
It takes an Act of Parliament. So what Act are you looking at that has displaced Harry.
Because it would be Harry and then Andrew.
If Prince William died and Prince George is a minor Parliament could make Kate Regent but it would have to be voted on.
I am pretty sure you are wrong.
https://commonslibrary.parliament.uk/research-briefings/cbp-9374/
The Regent is the heir to the Throne unless they have not reached the age of 18. In such a case, the Regent is the next in the line of succession who has reached the age of 21.