Xoanon here,

This is upsetting news, but the casting of Blanchett is not official. And as far as her UK agent, it is ‘News to her’.

While this in no way means that this is a false rumor, I think we could call her casting as Galadriel a little ‘hasty’. Her agent did say however that it could be very possible that things can change in the next few weeks. More to come