Yes, I'd always interpreted the last line 'Frightening' as Churchill's premonition/warning of what the eighties would be like under Thatcher but it could also be read like that. I don't think that this interpretation changes much about how we play it except perhaps that we need to believe that Angie is capable of killing her mother in the scene with her and Kit. The real animosity between them and Angie's vicious streak are definitely there in the script.