When I read the daily mail article, I just skimmed and thought the conversation described was a recreation of text messages. Now that I've seen the extract from the book, they weren't text messages.
It was a spoken conversation. Harry wrote, "They arranged a time to speak in the afternoon." And then he outlined what they said.
It wasnt text messages. They arranged a time to speak, got on the phone and the book outlines the conversation they allegedly had. Spoken word not texts. Have none of you read it properly?
The issue with a newspaper publishing her letter was copyright. She owned the right to the letter she had written. That's why she won the case. There is no copyright here. There are no messages. It was a spoken word conversation which Harry has outlined in his book.
Of course, it could be bullshit, they could have changed the wording, the same as everything else he had written. But there is no copyright issue.