Just thought it might be a good idea to flag this up - my elderly Dm gets masses and masses of junk calls, although I signed her up to the TPS....lots of them come from overseas unfortunately, which doesn't stop them.
Today she told me she'd been rung by someone who seemed to 'know' she'd been having these calls, and offering to sign her up to a call-blocking service at a cost of £4 a month. When she demurred (luckily she's very wary about this sort of thing) the woman kept pressing her to give her bank details.
Anyway, she didn't, fortunately, and they haven't rung back. They said they were called 'Cold Call Elimination' - a quick google reveals that they're basically scammers.
Worth being aware of, maybe. It makes me hopping mad that these leeches prey on elderly/vulnerable people who are usually far too polite to argue, and tend to believe what people tell them.