Just a quick point; I don't know enough to make recommendations but a wireless camera is still partly wired as you'll need to plug it in to the power; don't forget.
Update:
So the CCTV fitter thought it may be magnetic interference so now there's a thicker, more insulated cable in use.
Lets hope that stops the weirdness.
Main Menu
Guide
Record Mode
PlayBack
PTZ Control
GuideXVI
XVIAHD
HighSpeedPTZ
Color Setting
Output Adjust
Logout
If I open Main Menu I have: Record, Alarm, System, Advanced, Info.
I had a look in the DVR ( http://partizan.global/product/ahd-video-surveillance/ahd-dvrs/item/770-partizan-adh-18v-hd.html )
I can't work out how to manually change it into NV mode or specify when it should change.
I have placed the effected camera on it's own, un-shared power supply anyway.
As for warranty, yes it's brand new so replacing is possible but rather inconvenient.
For reference the Camera is
Manuf: Partizan
Model: COD-VF3CH
Version: SuperHD 4.1
http://partizan.global/product/ahd-video-surveillance/ahd-outdoor-cameras/item/1163-partizan-cod-vf3ch-superhd-4-1.html
Can't use URL bb code so sorry for the messy link; the link is to the manufacture and not a retail outlet so should have no baring on any ad partnerships on this website.
At the moment; there's 4 camera's plus DVR ran from two block type power supplies. I can't say if they all switch from Night to Day mode at the same time but I do know the other 3 camera's all work fine and do not have this issue.
When darkness falls; the camera in question will shift into the black & white night vision mode fine and seems to have no issues there in. The problem comes when day returns; the camera although well lit seems to stay in black & white mode.
If I turn the camera off then back on it will go back to color but this is absolutely not practical so if we can't resolve this issue the camera will need replacing.
Here are two images depicting the problem; one before then one after the restart of the camera.
Sorry about the image quality, taking a phone photo of a TV is never a good proposition; but they demonstrate the point.