After five phone calls from the same company in two days (one of whom had the cheek to say, when I told him to fsck off, that "it's for your own benefit, sir!"), I registered with TPS. The next day, when they called again, I demanded to speak to a supervisor as soon as they said 'This is Company X...', told him I was on TPS, got his name and the company's name and address, threatened to complain to the Information Commissioner, extracted a promise that my phone number would be deleted from their records and left him shitting his pants.
Listen to the change of tone in their voices when you say "what database did you get my name from? I have registered with the TPS, you do realise that there is a Â£5K fine for you calling me"
You can also register business numbers now (never used to be able to at the start) and also personal and company mobiles. Unless it's changed in the last couple of months you have to bend the truth slightly about the useage of mobiles (register them as private instead of business) but it works and has dropped the annoying sales calls to almost zero.
The ironic thing is that my business uses telesales and keeping the databases up to date with people who have registered on TPS is a right pain in the arrse! They have 30 days from the day you register to take you off the list.
If you really want to get them after the 30 days, DONT tip your hand and tell them about your registration, play along with them until you get all of the company details, then shop them