Thanks for the support browneyedgirl.
Harry the cod, to clarify, I'm a solo flight attendant and rely on pax to be co-operative. While I don't like being treated badly, it's something I can cope with when it comes from a full fare paying passenger. However, given the rudeness of the person in question (and she wasn't spaced out like the story you tell about a woman in distress, she was just plain rude), I don't think I acted harshly.
If I could change what I did, I probably wouldn't have said anything to her, but I would have reported her. I imagine she gets away with being a b***h throughout her life and not enough people tell her that it's not acceptable.