It's not calls from the UK that are the problem
The vast majority of annoying calls I got where from India or similar.
I bought one of those BT handsets that blocks calls and won't accept calls from unknown or overseas numbers. That was the only thing that helped.
I suppose I still do get the odd one from the UK, so this is helpful, but there has to be a solution mandated for FREE that will allow callers to block overseas and unknown numbers. Currently it is charged for (not cheaply) by telcos. This solution should be available free for privacy.
BT's privacy at home and the preference register are both totally useless and made no difference even to UK calls I received. Some chump who had the number before me (Mr Neally grrrrr) had given his number to everyone out there.