Will try and find exactly what Tina Brown offers up as evidence to compare.
Here's what I found - Anchor edition in PB from 2008:
p. 156: Diana at Highgrove, pre-wedding: "His valet Stephen Barry recalls them having tea together and later a light supper on a card table in the sitting room before driving back to London. A member of Charles' s staff, sonia Palmer, hints that it was more than tea. "Stephen used to say Diana always left iwth a glow and her hair freshly brished. Why did she neet to brush her hair if they were discursing on philosophy?"
Insert by me: We don't know if Stephen really used to say that. But if so: is it in his book? Or did he omit it for the same reasons as he omited the truth about the Train?
Brown goes on: "The tired old virgin thing again: the investment in that aspect of the fairy story had become so intense that it developped a life of its own. On the night of November 4, 1980, Diana attended Princess Margaret's fiftieth-birthday party at the Ritz Hotel in Piccadilly. What she did or did not do on two nights afterwards sent the Palace machine into near-hysterical overdrive....
From p. 157 to 164 Brown details the background of the Train incident and concludes: "Diana had now entered the zone of spin and would have to live there till the end of her life."
Another quote from the book, page 160:
For a number of reasons I have become convinced that it was indeed Diana on the Royal Train. If it was Camilla, why didn't Diana include the incident in her remorseless narrative of marital torture and betrayal in any of her confessional gut-spilling for Andrew Morton or Martin Bashir? Her later discovery that Charles was planning to give Camilla a bracelet became an operatic incident in her long list of hurts. For a girl on the verge of engagement it would have been a devastating discovery to find that her boyfriend was secretly two-timing her on the train while she was tucked up in bed at Coleherne Court..." Brown details her report with information from the Mirror, who had made a thorough investigation into the case and whose editor back then is still convinced that the research was serious and sucessful....