There is someone going around this area (Chatham) at the moment cold calling on residents, supposedly advising them about "telephone exchange upgrades" and quizzing them on their present telephone and/or internet arrangements. He claims to be from Talk-Talk – or at least did to me.
Obviously, this is not how such companies operate, and most of them have said so to their customers, i.e. 'we do not cold call by telephone, email or personal visit' or words to that effect.
I have checked with the council as a Trading Standards matter, also Citizens Advice, and let them know the details. They agreed with me that they are well aware that companies such as Talk-Talk do not cold call – so this is near-enough certain to be a scam.
Be Warned, and don't respond or give out any information!