Hurrah! I'm not the only one,...in England at least!
The dealer has done the work, dropped it back to me on Tuesday and the noise is gone :hocus-pokus: ! I hope it is a long term fix.
I think you should take yours back to the dealer, especially if its under warranty.
The noise you are describing is the same one I am referring to by the sounds of it. They replaced the calipers on the front wheels and it seems to have done the trick. Also, check that there is no noise coming from the rear brakes, as Lexus picked up on that too and replaced the clip/springs.
Good luck, I know how annoying that noise is. Make them fix it.