I completely ignored the placard which accompanies the British Museum Obelisk. You question made me go back and i realised i had the following on Flickr:
The inscription reads "Beloved of Horus, Lord of Mian (modern day Aniba) Living like Re forever"
I am out of my depth but this inscription sounds like it may offer a clue to the answer to your question. What do you make of this inscription? Would a God's Wife of Amun "fit" within such an inscription?