In my experience, registering with TPS doesn't really work. Not because they don't do what they say they do, but because 1) they can't do anything about calls from outside the UK and 2) telephone spammers these days use technological tricks to get around lists of banned numbers. For example, they'll rent unused blocks of telephone numbers from BT and use a call-switching system so that a call from an overseas call centre will appear to be from an ordinary UK number.
No, the best way to avoid getting spam calls is to not let your home telephone number get onto spammers' lists in the first place.
I learrnt this the hard way. When I first got online at home, I would happily add my home number to any online form that asked for it; within five years, I was getting up to a dozen spam calls a day and eventually had to ask BT to change my number! I then bought an old PAYG mobile phone from ebay (it cost about a tenner) and when any website demanded that I give them a telephone mumber, I gave them the mobile number. I still use it for that purpose today - it resides in a drawer with the ringer turned off; every now and then I charge it up and check it for non-spam calls and texts. And my main home number remains unsullied!
OK, not everybody can go the the extreme of changing your number. In that case, get a TruCall callblocker. I hadn't heard of that when I changed my number, but it's highly recommended.