I know that I am coming in a bit late to this discussion and I suspect the subject has now been resolved in some way or other but I did have concerns over the similar proposal some years ago and have never really thought that we have quite the right habitat in this part of Norfolk.
I have however seen White-tailed Eagles in inland wetland habitats in France, Hungary, Poland and along the Danube east of Vienna, I also believe that they have colonised Holland naturally in recent times.
Although we do not seem to have historic evidence that they ever bred on the great fens of Cambridgeshire, Lincolnshire and Norfolk before they were drained 400 years or more ago, from what I have seen in eastern Europe it wouldn’t surprise me if they once did.
As the new ‘Great Fen’ project develops over time I presume there will be opportunities for them to establish themselves into this habitat naturally, as have other wetland birds such as Egrets and Spoonbills done so elsewhere, and that in itself would provide proof, if that were needed, that they were right to be there.