Mayfair from the outside looks inaccessible; from the inside it's navigable and quieter than most of central London. The estate roads — controlled by the Grosvenor Estate — are swept and largely silent. The mews streets off Mount Street and Carlos Place are almost entirely residential, with the occasional news agent and no tourist infrastructure.
Shepherd Market is the surprise: a knot of narrow lanes and small restaurants hidden in the middle of the postcode, in the streets where the original Mayfair market was held from 1686 until it was suppressed in 1764. The galleries on Bury Street and Cork Street on the St James's side are worth the detour if the windows are saying anything.