In the above scene [From Wiki] “She flies to Paris with Miles for jet-set sophistication. She finds the wild party, beat music, strip dance mind game, cross dressing and predatory males and females vaguely repellent and intimidating, but Diana holds her own, gaining the respect of the weird crowd when she taunts Miles in the game. On her return to London, Robert calls her a whore and leaves her, for which she is not emotionally prepared. Ironically, Miles casts her as "The Happiness Girl" in the Glass Corporation's advertising campaign for a chocolate firm.”
My Synopsis: Vacuous lifestyle feminist mannequin uses her inherited looks and waist size to self indulge her way through several men under the guise of faux existential angst and vulnerability. Uncomfortable 60’s film with retro appeal which can still evoke a deflated “Brave New World” sensation in the viewer, of which the grotesque of the parasitical party scene is characteristic.
Someone else's more considered review is here