Aunt and Mrs B, we have the same, and despite the annoyance of someone who we miss out on, it works pretty well!
At least it stopped all the PPI scammers when they were in their heyday!
Just for the record, several chums, and me as well, have had a strange email from someone claiming that they know my password, and will send all sorts of 'page 3' stuff to contacts! Just ignore them, even if they have the password, which in my case was for an innocent website (I try and keep PWs different), and don't even bother to open the message, and definitely don't click on anything which looks suspicious, because it probably is!
The banks are very touchy about all this at the moment and are making even more fences to jump over, which is good news, if you play by the rules!