Fraser Bond are the leading lettings and property management agents for 50 Berkeley Street - London W1J. 50 Berkeley Street & 50 Stratton Street redevelopment in Mayfair, London W1. Astrea is will redevelop the two office buildings. Both buildings will be updated to provide high-quality modern office accommodation which is more sustainable, more energy-efficient and enhances the wellness of their occupants. The scheme will provide 270,000 sq ft of fully refurbished offices with private and communal rooftop terraces in both buildings. 50 Stratton Street will have a restaurant and retail space at.