Recently found - this 1969 press photo. The byline reads:

1/10/69 London. Christine Keeler (left), whose name figured prominently a few years back in a scandal that rocked the British  government attends a party in Chelsea 11/9 to launch a new book on the "Swingin' Sixties".  With her is photographer David Bailey actress Penelope Tree and singer Marianne Faithfull (right).

The book was Goodbye Baby & Amen. A Saraband for the Sixties. The text was by Peter Evans and photos by Bailey.

The sitters included Brigitte Bardot, Cecil Beaton, Marisa Berenson, Jane Birkin, Michael Caine, Julie Christie, Ossie Clark, Joan Collins, Catherine Deneuve, Mia Farrow, Albert Finney, Jean-Luc Godard, Mick Jagger, Brian Jones, John Lennon, Paul McCartney, Dudley Moore, Rudolf Nureyev, Oliver Reed, Keith Richard, Peter Sellers, Jean Shrimpton, Barbra Streisand, Andy Warhol, Franco Zeffirelli. Presumably some of these illuminati were at the party..