Haven’t bothered going in a while, as I live in a “safe” constituency held by the one party I dislike the least out of the two parties to choose from, but if I recall correctly, you only have to register with your specific polling station when you move to another residency. Although you also have to apply for a specific voting photo-ID for each election if you don’t already have a driver’s license or other govt-issued photoID.

Neither is an automatic process, and the only thing we get in the mail without asking for it is notification that an election is about to happen, and various adverts from each of the parties running.