Harry is loathed in the UK!
THE SPARE and all of the subsequent T.V. interviews have made him persona non grata there!
Parliament has already shot down every single attempt, Harry demanded for "protection", when/if he returns to the UK, with or without the family in tow.
Since you claimed that Catherine would automatically be Regent show me the law that states that.
I have shown you the law from the House of Commons that shows you are wrong. Show me the law that says you are right.