I read the whole thing too- I setlled down with a nice cup of tea and really enjoyed hearing about what you've been up to and what B is up to, and how great your conversation was.
I agree with Al that B sees you because he wants to. I guess the thing is to try and build the friendship a little more and then perhaps bring in some harmless flirtation, as Jody suggested Julia do in her friendship with H. Do you flirt with B at all when you see him? Eye contact, or a flirtatious type of banter perhaps?
Are you going to see each other this weekend, after the festval? Sorry if I missed that in your post.