Escorts in Marble Arch, W1H, with Oxford Street running out into the park

The arch itself is a piece of Nash, cut in white marble to stand at the front of Buckingham Palace, then shifted here when it proved to be in the way. It now sits marooned on its own island of paving at the junction, too big for the traffic circling it and rather magnificent because of it. Cross to the park side and you are at the north east corner of Hyde Park, where the speakers still gather on a Sunday and argue with anyone who will stop.

Behind the junction the streets calm down almost immediately. Great Cumberland Place curves away in a crescent of Georgian brick, Portman Square keeps a private garden in the middle and two of the better hotels on its edge, and Seymour Place and the little lanes off it hold the neighbourhood restaurants that the shopping crowd never finds. Ten minutes east, the department store windows begin.

W1H fills up with people who came to London to do something specific. Buyers in for a week of appointments, families whose grown children are elsewhere for the evening, transatlantic guests who chose the hotel for the airport connection rather than the address. The evenings they ask for are unshowy: dinner, conversation, an early enough finish to be useful the next morning.

There is a second pattern, and Bella sees it most on Fridays. Guests who have been at meetings in the City or Canary Wharf all day and want the last part of the evening to feel like a holiday. They arrive back around eight, ask for £750 of the evening or £1,050 of it, and want somewhere close, good and quiet. This corner supplies all three without argument.

W1H 7DL stands right on the junction, the largest and the easiest to slip in and out of. W1H 7TW hides behind the crescent on Great Cumberland Place, a row of townhouse fronts with a modern hotel behind them. W1H 5DN sits on George Street, five quiet minutes north of the noise.

W1H 7FD is the surprise of the group, Japanese in tone from the lobby scent to the whisky list and by some distance the calmest bar in the postcode. On Portman Square, W1H 7BH looks over the garden with a grand front door, and W1H 7BG sits a few doors along with the busiest restaurant of the six.

Six places on a map, that is all. No hotel at this junction deals with us, and none of them learns a thing about your evening from this office. She can wait for you in the lobby, or ride up by herself once Bella has taken down which room, and which surname it answers to.

The Central line calls at Marble Arch, 1 minute from the junction, four stops short of Bond Street and under twenty minutes from the City. About 6 minutes north west, Edgware Road adds four more lines, among them the Circle and the District, the Bakerloo and the Hammersmith and City, for anyone bound for Paddington or the west. Bond Street itself, roughly 8 minutes east along the shops, brings the Elizabeth line and the airport run.

A car brings her in, its first two zones counted inside the quote, so no sum is added later. From Bella's yes, W1H usually sees her in about an hour on the night, more when Oxford Street is at its worst or a Friday is in full cry, and the chat carries the exact time once she is on the road; plan it days ahead and she is there on the hour picked. Her fee comes to her from you as she steps inside, and which room and which surname were written out before she left.

Rosa walked this one. A guest on Portman Square who had spent the day in showrooms and asked Bella for somebody easy to be with, four hours from eight. Chestnut curls, suede boots, an opening line about the lift music that had him laughing before the doors closed.

They ate late and locally on a side street she knows off Seymour Place, walked back the long way round the square, and finished in the Japanese bar two minutes away with a whisky each and a very serious discussion about soul records. Four hours on the meter, £1,300, and a text at half past midnight that said only: perfect.

Rosa and Liana live in Marylebone, just to the north east, and both treat Portman Square as their own back garden. From Paddington, on the western side, come Laura with her green eyes and her Italian road trips, Nora with a sketchbook and a taste for something sparkling, and Vanessa, who can name a scent across a room.

Samanta and Luna come up from Mayfair when the evening wants a little more polish. Seven names within a short drive, which is why this corner is one of the better bets for a booking made after nine at night.

South down the hotel row runs Park Lane, from W1K 7TN at the top to W1K 1QA in the middle. Straight ahead through the gates lies Hyde Park and its perimeter suites. South east, five minutes on foot, Grosvenor Square opens up, and east along the shopping street you reach the windows of Bond Street.