Now here's a radical idea. Instead of worrying about where the cameras are, why not try sticking to the speed limits if you're that worried about points etc. I personally couldn't afford to lose my licence, so I make a conscious decision to keep my speed within the speed limit. Not being self righteous, I can understand the urge to go faster, but the consequences of getting a speeding ticket are not worth the risk for me.
The GPS databases show you only fixed camera sites and mobile camera sites, none of them can prevent you being caught by the good old bobby on his otorbike or in his car with a handheld speed detector, or the bobby sitting in an unmarked car in a side road.
The laser/radar detectors are great, for telling you when to expect a ticket in the post. As said above, unless you are very lucky and pick up a stray reflection from a car in front, the chances are by the time your detector starts to whine you've already been clocked. The radar devices you might have more luck with, but the laser ones have a very narrow beam with very little scatter for the detector to pick up.