Ah, WorldCon! I envy you the trip. I shall not be there myself this year, though I'm thinking about London in 2014.
When you see Paul Cornell, tell him your friend Janna really enjoyed London Falling and learned things about storytelling by reading it (which is absolutely true) (as if you'll remember). (Also tell him that I worship him from afar for his work on Doctor Who.) (OK, you can skip that last part.) Thanks in advance. :-)