My favorite quiet hotel in central London is the Westbury. A smallish hotel in Mayfair, on Conduit St., nestled between Bond and Regent streets, it is within easy walking distance to the hustle and bustle - Oxford St., Regent St., Carnaby St., Piccadilly Circus. Stone's throw to Green Park and Hyde Park. Quiet A/C, nice lounge and great breakfast. I believe it is now affiliated with SRS. Staff are absolutely wonderful. They usually have specials on weekends.