Thanks for looking into it.
I checked & found my installed binhex/arch-privoxyvpn docker version was 7 months old for some reason - strange as I only installed it for the first time last week (on two different Unraid machines as well - both grabbed the old version) .
binhex/arch-privoxyvpn latest sha256:62829fd90130a29e48320faacc9c0ffc249a0cc1e13a56a4699652f2e00e684e 818db7544137 7 months ago 685MB
Anyway, forcing a check for updates in the Unraid Docker GUI page found the latest version which I installed and tested - works well as you describe.