From the GenCon 2012 website:
Shadowrun Missions Living Campaign: London Calling Series! The Explosive action in London continues. Can you survive? Missions Character Required.
moved to (Unpublished Products) on August 18, 2016
According to the Missions Coordinator, this product will likely never be published as a separate adventure.
It was available for Catalyst Demonstration Team Agents for use in the SR Missions.
The adventure is included in London Falling.