www.truecall.co.uk is the only thing which has ever worked for me.
Looking at the call stats its rejected (for varying reasons) 78.7% of all incoming calls - I also have some options set which mean I never hear the call but robocallers get sent to the message manager where they stay connected for 4 minutes. Might not cost the spammers much but we do what we can to bump their bills up
There are various different "models" now - AIUI they're physically all the same, just different subsets of the same firmware. The one I have does everything the new models do but I don't know which model corresponds to that now.
For intl (or indeed any) calls you can block them all but specify a "breakthrough" code to give people which will override that.
Its not a phone but it works a lot better than anything BT will supply you - I am very dubious about any teleco really wanting to give you a full set of blocking features as they make LOTS of money from the spammers.....