I have a similar situation in my two lot scheme where the other owner has installed a surveillance camera on common property (without consultation) which films the common driveway indicating every time I enter or leave the property and it also films every visitor I have to my residence. No one can give me a clear and decisive answer to the invasion on my privacy and that of my guests.
There is a small sign alongside the camera saying you are on view. You would have to be at least 1 metre away to be able to read it.