For anyone that follows later,
I found the intrusion detection MUST be set with the NVR first. Once enabled and saved then log into the cameras and configure using the intrusion detection options. Not sure why but if I tried to enable in the camera it would not work unless I enabled it for each camera in the NVR first if that makes sense.
I still have problems where it does not recognize an object moving into the per-defined area sometimes until it is well into the area. I could negate this with pre and post record but smart events dont seem to pay attention to pre/post record so thats useless. I think I can still use it to reduce false negatives though. What I might do is set my intrusion detection area and then use the advanced options in motion detection to create an area at the entry points to the box. These seem to not suffer the same failings of not identifying objects and will also catch a pre/post record. By then if the object moves into the intrusion detection area and is picked up half way it wont matter because the NVR will already be recording.
The intrusion detection area will mean I wont need to spatter little boxes all over the place for motion detection in an attempt to miss areas of reflection/shadows but capture traffic.
That leaves me with the only other short falling with the hikvision cameras. On power outage the cameras all default BACK to "normal" mode in the motion detection areas. However, I have written a short batch script that
downloads the xml file off the camera, changes the flag from 0 to 1 and uploads it back. Basically setting the motion detection back to "advance". It seems to hold the settings so all good. Would be nice if hikvision fixed that bug tho.