Fraser Bond are the leading lettings and property management agents for 18 Grosvenor Square - London W1K. 18 Grosvenor Square is a mixed-use building in Mayfair, London W1. 2020 - Finchatton is advertising a 4-bedroom apartment for sale with magnificent south-facing views over Grosvenor Square. The 3,469 sq ft apartment is located on the third floor of a period building overlooking Grosvenor Square. The building benefits from a lift and a 24-hour porter. Neighbouring Buildings E - 15 Grosvenor Square - adjoining. W - Twenty Grosvenor Square - adjoining.