I'm not being paid but the entrance fee covers the venue I think.
Also, rather flatteringly, I am a keynote speaker at the second Middle Ages in the Modern World conference at the University of Lincoln in the week of 29 June 2015.
Finally, I've written a chapter for an academic collection on Medieval Science Fiction (together with our own Michael Flynn) that may be out later this year.
I'm sorry, James, but I don't think I will be able to make the flight to London to attend any of these (my personal Lear jet is being repainted!).
But I am interested in Medieval Science Fiction (I used to read a lot of Sci Fi in my misspent youth, and observed a major change in the genre over just a few decades - from space cowboy and 'monster" fiction in the 40s and 50s (before I started reading) to much more psychological stories in the 60s and 70s - so it would be interesting to see what they wrote back then.
I also used to read vast amounts of SF and Fantasy. Alas, I don't think the collection I'm contributing to has much on science fiction written in the Middle Ages, but takes a much broader view. I'll post a link when it is out. I'm slightly afraid it will be one of those very expensive academic books that even libraries can't afford, but we shall see.
My understanding was that fiction, SF or otherwise, was a relatively late development, Robinson Crusoe (1719) being the first novel. In your OP, I took it to refer to SF set in the Middle Ages, in the vein of: A Connecticut Yankee in King Arthur's Court.