please do not think that I am accusing you of selling a fake.
I am only saying what man other people MAY be thinking.
What surprises me here is that you have already sold one at Christies for an excellent price, completely authenticated. Therefore, why not sell this one through the same venue?
As has been said, Ebay is rather anonymous and has a reputation for 'iffy' bottles from less than genuine sellers. Now, I think that you are genuine in everything you say, but quite honestly and in my opinion, Ebay is not the best platform for these lesser known and more expensive / exclusive bottles.
My advice would be to speak with someone like Martin Green at McTears and have it included in his next auction.