So my info was good then.
Thank you for the link some people have got the impression that they only pay one £1.75p a month. But the mail suggest not.These are the relevant bits.
"Previously free BT Answer 1571 and BT Privacy with Caller Display will now each cost £1.75 a month. Customers will be 'opted in' if they have ever used the services in the past."
BT Answer 1571 is an answer phone service that callers can access by dialing '1571'. The company said that it will consider any customer who has ever dialed 1571, even if it was several years ago, as having opted into the service and will add £1.75 to their monthly bill. They can avoid this by responding to the letter they will receive next week to opt out, and BT said they can cancel at any time.
BT Privacy with Caller Display has been offered for free since 2005 and was taken up by those who wished to avoid nuisance calls. Customers needed to request the service, at which point BT would have also signed them up to the Telephone Preference Service to avoid cold-calls. Anyone that requested it will now have £1.75 added to their bill unless they act.
Customers opted into BT Answer 1571 can continue to get the service for free if they agree to sign up to line rental with the company for another year."