There was still a strong predominant black presence in the Europe well after the Moors. Ben Franklin talks about this in great detail.
Is the swarthy olive complexion your only reference point for her being black?
I've got a ton of books in my basement on the Tudor age I could look at, but it would yield a result of confirmation that she was white.
Most prominently there was debate that she was a brunette or a red head. Never heard of this angle before.