what to do what to do

I say go for it. You only live once!
I will admit however that it is easy to give such advice when one is in a secure relationship already and halfway across the world to boot.
I think if Next Room Bee is showing signs he is willing you should make a goer of it. Think of the fun "when I was living in London" stories you'll have! Drunken middle of the night pashing (sorry, Snogging) on the living room floor when someone comes in and your bra is on the couch stories!!!
And as for friend who stole him initially's feelings? She didn't consider you then, so I don't think she deserves consideration now.
And that's my two cents.