Sledgehammer, eh? Sounds divine! I really love this wine, find it refreshing, well balanced and a bargain.
I don't think I have the same reaction to it you do. Sauvignon Blanc often evokes grapefruit but I find it to be more subtle and complex than you did. Cat piss and overly tart grapefruit are, to me, not pleasant aspects of many Sauvignon Blancs. The Whitehaven, though, is just citrus enough and is amazing with many foods, particularly fresh seafood like raw clams or oysters. And as you noted in your PM, it's great for clearing the palate and cutting away even fats and garlic when going from one dish to another.