Before paying for the Tomtom alerts look at the ones from PocketGPS. I can compare the two as my wife got a free one year subscription for her Rider but I use the Pocket GPS ones on mine. Same sort of cost but I have found many errors on the Tomtom ones and they are slow to update new cameras. For example, two new cameras were installed near me in October last year. The end of October PocketGPS included them but it took three months for them to appear on the Tomtom database.
You simply download the files, stick the Tomtom SD card in the computer and copy them all to the map folder, e.g. Western Europe. The first time you install them they need "activating" on the Tomtom which basically means scrolling through the POI list and setting each one as an alert and choosing the alert tone. Easy instructions come with the files and it only has to be done once. The updates just need copying across.