I have now been to the launch of a small, but beautifully produced, book called The Essence of Mayfair, published by British Land in celebration of its new building development in Clarges Street.   What became clear is that everyone has a different view of Mayfair.   For Jeremy King, the proprietor of the Wolseley, it is, not unnaturally, a  neighbourhood of grand hotels (The Beaumont), restaurants and fine car show rooms (although the Wolseley was short-lived as a car show room).   For Kathryn Sargent, the former head cutter at Gieves and Hawkes, it is somewhere where Terence Stamp might emerge from Albany in his dressing gown to post a letter.   For Rupert Sanderson, it was once a neighbourhood for men only – guns, suits and clubs – which is now responding to the invasion of international fashion.   There is a sad little note inserted in the book to the effect that Allens, the long-standing  butcher on Carlos Place, is moving.   So, the question is how long this mixed ecology can survive.