"Theirs is a new model and they never wanted to go back to the old one, even if they do come back to the UK.
"The review is intended to keep the door open, but Harry could see the downside of this because this wasn't about them changing their minds."
The new biography, Finding Freedom, retells the events leading up to the decision by Harry and Meghan to leave the UK and give up their regular duties in an attempt to strike out commercially and pay their own way.
The bills for their security detail are no longer paid for by the taxpayer, and Scotland Yard does not provide officers to guard them in the US.
Finding Freedom alleged that the Duke believed that the "old guard" at Buckingham Palace disliked Meghan and wanted to make her life difficult. The couple have insisted they offered no interviews for the biography's authors nor contributed to it. The book also alleged that the rift between Harry and his brother, the Duke of Cambridge, was sparked when William questioned Harry's relationship.
It is claimed that William told him: "Take as much time as you need to get to know this girl." Harry believed the comment was "snobbish".
The review allowed Prince Harry to hold on to some patronages and titles, said insiders, that allow him to maintain links with the UK. The pair had been expected back for major events such as Trooping the Colour, but those plans were scuppered by the pandemic, according to a source close to the Sussexes.