I'm just not sure why the circle. What does that achieve?
Well, a normal approach of a helicopter would be to turn it into the wind for the safety of the helicopter and it's occupants during the landing phase. From the video (as an example) I would recon the helicopter comes flying from a direction where it travels with the wind, flies a bit past the landing in order to face into the wind for landing.
These ''circles'' are very normal.
Hope it explains your question.
As I said a friendly reminder shouldn't hurt, and it might be they have got new pilots which is unaware of your situation. Most pilots are sensible enough to avoid overflying certain areas if they know about it.