Cindy, twenty-eight floors above Hyde Park

Cheerfulness is scarcer in W1 after dark than one might hope, which goes some way to explaining Cindy's diary. She is 168 cm and slim, with the settled posture that a morning yoga practice leaves behind, and her blonde hair hangs past the shoulder blades in loose waves that no salon has managed to copy. The eyes are blue, a clear coastal blue. She dresses simply and well: pale silk, tailored trousers, a slim watch on a canvas strap that has been to sea.

Sporty without being tiresome about it, she is easygoing in a way that loosens the stiffest guest within a course. Mid twenties; English, spoken with an unforced friendliness. Sailing is the great outdoor love, dinghies first and larger boats since, and she reads a sky the way others read a wine list. A small film camera goes everywhere with her. She is a patient listener and a quick, generous laugher. Yoga keeps her steady, whatever the week has done.

For an evening near Park Lane she chooses Galvin at Windows, high in the London Hilton, twenty-eight storeys above the Park Lane traffic, where the whole of Hyde Park turns violet at dusk and the lights of Knightsbridge come on beneath you. She will want the table by the glass. She will photograph the view exactly once, put the camera away, and give the remainder of the night to the conversation.

Chelsea is home, a short ride from Park Lane and its row of hotels. Her hours run from late afternoon into the early evening, and a line through booking is all Cressida needs.