RCF when you saw the bird, did it look more grey or more brown? Alice was very very brown last year, no grey at all. The cheekpatch looks too small for it to be Zeus so maybe your Tower bird is Hurricane checking out the new digs. Also, Alice is a big bird. In comparison with Hurricane, she's a very big bird.
It took me a minute to figure out what direction you were looking from but once I figured it out (thank heavens for ladders) I realized where she's sitting. Now if she would just wander over to the other side, she could see the where we put the new nestbox .... (fingers crossed)