Another NHS trust has teamed up with Sitematch London to meet with developers at the event on 6 November.
Subscribers to Sitematch London can now view details of CIL charging schedules of participating councils.
The opportunity to win a bottle of single malt Scotch whisky or a bottle of champagne is still available to those taking part in the Sitematch London online survey.
More than 20 sites in the London Borough of Haringey have been added to the Sitematch London database, so that developers and the council can discuss them at meetings during the next Sitematch London event on 6 November.
The West London Mental Health Trust has confirmed it will attend the Sitematch London event on 6 November to meet developers and discuss options for its property assets.
Barts Health NHS Trust is the fourth trust to join Sitematch London to meet developers.
The Royal National Orthopaedic Hospital NHS Trust is the first NHS Trust to join the Sitematch London programme.
Twenty-one London boroughs are looking forward to meeting developers at the next Sitematch London event, at City Hall on 6 November.
The Greater London Authority is aiming to have plans for all of its surplus land by 2016, according to deputy mayor and director of housing Richard Blakeway.
A site on the Sitematch London database went on the market on 29 September 2012.