If there are any mains sockets near windows overlooking it, might be worth setting up a camera.
GoPro-style action cams normally have a very wide field of view so you can spot people loitering or scouting. I have an SJCAM5000 which does at least 2K video (so zooming in at the target won't give you pixelated fuzz), has motion detection, can do looped recording (delete oldest video when card is full) and has a load of features that make it good for other purposes. Cost about £120.
If there are any mains sockets near windows overlooking it, might be worth setting up a camera.
GoPro-style action cams normally have a very wide field of view so you can spot people loitering or scouting. I have an SJCAM5000 which does at least 2K video (so zooming in at the target won't give you pixelated fuzz), has motion detection, can do looped recording (delete oldest video when card is full) and has a load of features that make it good for other purposes. Cost about £120.