I was going to place a micro here (well I did place a micro here) but in looking at the Broadgate website to get info to write in the listing I found these great web cams.
There are four cams all looking at the "ice rink" area by Liverpool Street station.
The arena is an ice rink most of the year round but in summer it changes to host lots of things from simple promotional stands and musical Performances, to horse displays, street theatre and sports events such as Beach Volleyball and Human Table Football.
To claim the cache you will need to stand in view of one or all of the web-cams and get a friend to log on to capture your identifiable picture. You must also write in your log what the area is being used for on the day you are there. (not that we will not be able to see that from your photo.
link to webcams
Call up the web page with the webcams on – maximise the webpage, Press <alt> and <Prt scr> at the same time this will copy the whole active page, Then you can paste this into a Microsoft application (word or paint etc…)