The Blackstaff has so many clues pointing at it that I have to go with it being the walking stick, besides, Eldest Gruff went to Harry's party in Arctis Tor with the stolen walking stick of MW? cannot see that happening.
MW has the power to get it back, surely, so there must be a compelling reason for it to remain where it is. But we have WOJ that they stole the Blackstaff and the original owner wants it back, so that implies that the White council can keep one of the most powerfull artifacts of Faerie, use it at will, with little or no reprecussions?
there is at least one other thread about the other names of MW, looks like I have to take my speculation about Annan back, thanks for the update Ms. Duck.