Grosvenor has today announced the start of work at three new flexible office developments in London’s West End – Radstock House, 67 Grosvenor Street and Holbein Gardens – marking a major milestone in the strategic evolution of its UK office portfolio. 

Totalling 50,000 sq. ft, the developments realise Grosvenor’s commitment, first announced in April 2024, to convert 20% (approx. 300,000 sq. ft.) of traditional office space into flexible and fitted workspace. Grosvenor is on track to exceed this target, with flex set to account for 22% of its UK office footprint when the three new sites open in Spring 2026. 

• Radstock House, Belgravia: Situated at 5 Eccleston Street, Radstock House offers 13,855 sq. ft. of architecturally refined workspace, including 4,493 sq. ft. of fully managed flex space. The building features a rooftop terrace with panoramic views and is located moments from Victoria Station and Eccleston Yards. With special events for occupiers, it will deliver hospitality-style service and exclusive member privileges.  
• 67 Grosvenor Street, Mayfair: Located in the Mayfair Conservation Area, this 10,702 sq. ft full CAT-B refurbishment of two historic townhouses built in 1723 will deliver a heritage space with modern internal features. Designed by architect De Metz Forbes Knight, the scheme includes a club lounge, boardroom and garden. 
• Holbein Gardens, Belgravia: This 26,500 sq. ft. repurposed 1980s office building is one of London’s leading net-zero workspaces. Spanning six floors, the building is being repositioned from a net-zero HQ to a fully managed flex site. 

Grosvenor’s flex portfolio consists of 10 dedicated sites in Mayfair, Belgravia and key regional cities, alongside 12 fitted and managed offices. With average occupancy at 89% and renewals tracking at 80% year-to-date (up from 66% in 2024), Grosvenor has seen demand for premium, adaptable workspaces continue to grow. 

Both 67 Grosvenor Street and Radstock House will be degassed, with the transition to fully electric power supporting EPC improvements from D to B, while Holbein Gardens, one of London’s leading net zero offices, has an EPC A rating. By prioritising reuse and low-carbon materials, and with all three sites sourcing certified renewable energy, these new offices reflect Grosvenor’s commitment to sustainable retrofit and support the company’s goal of becoming a net zero business by 2040. 

Piers Townley, Director of Offices and Flexible Workspace at Grosvenor Property UK, said:  

“These three sites showcase our approach to flex - providing turnkey, design-led offices with a customer-first mindset, alongside hospitality-style service, flexible lease terms, and premium amenities in some of London’s most sought-after locations.” 

“We’ve seen consistently high occupancy across our flex portfolio and renewals increase significantly in the past year. Expanding our flex footprint across the West End is creating exceptional, sustainable workspaces that enhance our neighbourhoods, diversify our portfolio and maximise the performance of our assets.” 

Find out more about the London locations at: Office | By Grosvenor. 

Published first in Green Street News.

About Grosvenor

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Grosvenor is an international organisation whose activities span urban property, food and agtech, rural estate management and support for philanthropic initiatives.

We are a values-led business which represents the Grosvenor family and share a common purpose - to deliver lasting commercial, social and environmental benefit - addressing today’s needs while taking responsibility for those of future generations.  

With a track record of over 340 years, we work to improve urban property and places in many of the world’s leading cities, promoting sustainability within the built environment and enhancing the wellbeing of customers and communities. 

Our UK property business supports c1,000 businesses and tens of thousands of residents and workers across London’s West End each day. We also invest in, create and manage sustainable neighbourhoods across England. As a 1.5oC aligned company, pioneering change and new ways of thinking about property we aim to ensure our places benefit both people and the planet over the long term.