Thanks for replies guys. I'm glad I posted before buying anything.

Quote Originally Posted by SmartWombat
Motion cameras usually work on detecting motion in the image, by subtracting frame1 from frame2 and looking for the difference. It has to be set so that it isn't triggered by trees blowing in the wind, for example, but that kind of visual motion detection would work fine.
If it has a separate Infra Red detector for motion, then that won't work very well through glass at all. So that rules out the Maplin sentry camera.
The sentry camera would be fine outside the car, watching it, with 30 hours battery life on AA cells, but of course once the flash has gone off they know where it is and can just steal the camera.
Bummer Would've been perfect given the long battery life. Also looked at a Bushnell model http://www.bhphotovideo.com/bnh/cont...s=REG#features which says "is activated by motion, and it uses a passive infrared sensor to detect motion out to 45 feet. " so I guess that one won't work for the same reason.

Quote Originally Posted by SmartWombat
If your car battery is in good condition, 12V cameras take so little power that you can run them continually, not sure about the recorder though.

Try N89FX and B42LW from Maplin.
Thanks for that, they look like they'd do the job. Only thing unsure of is how it would be powered when the car is off. Unsure if these have that lighter socket type connectors, in which case ignition needs to be on as there's no power to that socket in my car until engine is on (I use for charging me phone too).

Hopefully this doesn't sound stupid but what about a standalone 12v battery that I could just keep in boot for hooking up camera.

So annoying having to go to these lengths. it's a secure car park so it's definitely a resident.