Question Author
I only have a BT landline, no mobile. Adequate for my purposes. But it has no caller number display, so I rarely answer the phone, and most people I know, know that, and that if they leave a quick message, I'll get back to them ASAP.
It doesn't matter if they know they're blocked - they will realise that when I don't call them back.
I take it that when you talk about 'tap the number', and 'scroll down', this refers to a feature which mobiles have, and so they're unavailable to me on a landline!
The blocking option sounds worth checking out - I'll have to speak to BT about that one.
Thanks everybody.