Speechless is right that you might have to pay for the speedcams dbase. However, all the dedicated camera alerters I looked at (inforad, snooper, microfuzion etc ) all wanted a lot more than £2 per month so if the pgpsw dbase does go chargeable, it may well be cheapest.
Speedcam alerters are illegal in Germany (maybe elsewhere?) so if you do plan to add that facility to your satnav, you need the ability to control whether it functions or not.