[Margaret Pilkington]

If you are signed up for this service then the caller has to have your permission to call you.
My suggestion when you get one of these phone call is ask the caller if they have your permission, and when the premission was given.
If they cannot respond(because you haven't given permission) then threaten to contact the Information Commissioners office with their details. Tell them that the ICO take a dim view of unsolicited calls as they are illegal, and it may result in severe penalties for the firm concerned.

Automated calls.
I have had a number of these recently. Ok you can just put the handset down....but y ou can be very sure that if you do this they will continue to call.
I stayed on the line and pressed the number as directed and was put through to a debt management company.
The heavily accented voice on the other end gave the name of the company(lovely)......I asked if he knew that these calls were illegal...he spluttered a bit and asked if I wanted my name removing from their calling list......well, of course I did! RESULT....no more calls from this company.
I hope that my suggestions will further help you to eliminate this electronic nuisance from your life.