Silent call. Phoned back, got the same message as everyone else, phoned it, confirmed, then called their 0800300220 sales line to waste some of their time.
Stressed that I'm on the TPS (although I have a horrible feeling I've managed to drop off it *again*, as this is the second spam I've received in two days) and that what they've done is illegal, and they're going to contact their marketing department. They've said they'll remove me from all marketing campaigns in the future, but that it'll take six weeks. Bonus: no paper spam, either. And I wasted about twenty minutes of their time.
UK call centre, clear sound.