It could simply be a pilot practising night time approach and landings to heli spots on top of buildings? Either a new pilot getting shown where they are, or pilots getting the currency night flights they need?

It's not an easy task to shoot an approach and land on a building at night, your external references are easily diminished, along with obstacles like antenna's or other obstructions.

Can anyone ID the buildings to see if they are dedicated landing points for heli's?