Workspace, the FTSE 250 group which owns and manages about 100 properties in London, has agreed to sell a residential redevelopment site to privately-owned property group Grosvenor for 51m pounds.The land is part of the 11-acre Biscuit Factory site in south east London. Workspace obtained planning consent for 800 new residential units on seven acres of the site earlier this year. Under the terms of the deal, Grosvenor will also build for Workspace at Grosvenor's expense a new commercial building on the land retained by Workspace which will increase the amount of business space at the site to 270,000 square feet. It will also be responsible for landscaping the site and creating a community park.Workspace Chief Executive Jamie Hopkins said: "Once completed this will be a thriving residential and business location, providing Southwark with its largest hub for small and growing businesses."This partnership will deliver significant value for our shareholders and considerable benefit to the local community."Shares in Workspace were up 1.1% at 477p at 08:37 on Thursday. TB