Well, actually, I heard that they are being sold now, before a planned book comes out.
And I think that the facts are a bit garbled in the account. A grandson of G.D. Olga would not have the letters which she had written to her sister. The grandson is most likely one of G. D. Xenia's, don't you think?
Nor are these letters newly discovered.
I can't find the reference right now, but they surfaced several years ago, but are only now being put up for auction.
It also seems a bit of an exaggeration to say that G. D. Olga "hated" the British in general.
Still, it's great to have this material available -- more threads in the Romanov tapestry.