It's one of the odd interludes that don't quite work, like the running Simon Armitage gag. (You have a vision of an editor saying 'I don't really get this' and RW saying 'But it really happened!' And no, no idea why, even if they did believe Moth was the Poet Laureate, she would depict the beautiful PA and the nanny massaging a topless Moth while his wife took photos, and Grant asking whether he could use the photos for 'publicity' for a wine business...?)
I wondered if RW had included it because 'Grant' tells Raynor a tall tale. According to him, he tramped with a knapsack all over Europe, living on fresh air, ended up sleeping rough in an Italian vineyard, learned everything he could about wine, then came home and started wine trading out of a disused warehouse until he made his millions and attracted 'all the beautiful girls in his household'-- then his wife says 'Take no notice. He studied wine in evening classes and his father got him a job with a wine trader.'
After which there is the now much-picked-over line:
I thought about Grant’s tale and why he felt driven to tell it. When you tell a story, the first person you must convince is yourself; if you can make yourself believe it’s true, then everyone else will follow. Grant wanted to be the person he had created: hard done by, struggling through life’s adversities, but making good on his own wits, rather than the son of a wealthy father with connections.
She goes on to say their own story was 'created out of self-protection' to avoid being 'othered' and rejected as homeless, by changing only one word in their otherwise true story, that they had 'sold', rather than 'lost', their home.