There is very little that anyone can do about these calls. You can register with the TPS if you like but it will make a small amount of difference, if any at all. The company that featured in that rather stupid program on BBC 3, The Call Centre, was recently fined for ignoring the TPS. Foreign companies bypass the TPS with complete indifference.
You can try changing your phone to one with a answering machine built in, and then use it to filter out this nuisance calls. But it won't stop the phone from ringing, when you are sitting down to your dinner, or just got into the bath, so limited value really.
What I have done is to take the phone off the hook completely, and only use it for out-going calls. I have let everybody know my Mobile number, at least the ones I trust. Friends and relatives know that its best to text me before ringing, if its urgent.
It isn't an ideal solution by any means but its the only way that you can stop these blo*dy completely.