I personally wouldn't assume a more expensive action camera would capture number plates better. Some of the very cheap action cameras have crappy 1.3MP sensors meant for security cameras and they have blocky pixels that capture a lot of light per pixel. I was mucking about with a action camera based on a general plus chipset which is the worst chipset for action cameras and often used in those awful children's digital cameras and other very low cost digital cameras and I'm sure it had great night performance. The sensor had the least accurate colours I've seen I think, not very true to life at all. As sensors go up in megapixels it becomes harder to be light sensitive. I think Panasonic/Lumix released a 12MP compact camera not that long ago actually less megapixels that the previous model because it gave such good all round performance from that sensor with regard light sensitivity. Panasonic TZ70 which gives far better night photography and allows faster shutter speeds during the day or smaller apertures etc over similar cameras with more megapixels and less light sensitivity.
Light Superzoom Travel Camera | DMC-TZ70 | Panasonic UK & Ireland
Capture breathtaking photos on every adventure with the LUMIX TZ70 superzoom travel camera, the perfect travel partner to accompany you whilst discovering the world.
www.panasonic.com
As action cameras go up in megapixels their light sensitivity of the sensors reduces and they have to compensate for that somehow, it could be slower shutter speeds or wider aperture etc. They almost all use tiny sensors with poor light sensitivity anyway so you can't assume that a camera that gives amazingly detailed video in good light will also be competent at night.
