Using prefix 1470 - two questions

[David100]

Arising from a query raised and solved regarding Caller Display, a friend still has difficulty using his BT landline to call me. I gave him the advice to add the prefix 1470, which he has done. Now when calling me, using the prefix 1470, he was asked whether he wished my number to be added to his Black List. He became suspicious and didn't continue.

Is this a normal recorded response when using the prefix 1470? 

If so, what is the significance of my BT telephone number being added to his BLACK LIST?

When adding the given prefix, should he drop the initial zero of my area code?

My thanks to anyone who can clarify the described situation.

David

[Les-Gibson]

Perhaps your friend dialled 1471 by mistake instead of 1470?

[David100]

Thank you Les-Gibson. I have asked my friend to check this point.
Can you answer my second question regarding the area code zero?

[licquorice]

No, you don't drop the leading zero

[David100]

Thank you licquorice for that confirmation.