Last time, I forgot to mention that part of the idea here is to have Harry and the Potters perform live music at the event. The good news is that they're interested. The bad news is that they plan to be reading some book that evening. New current thinking is sometime in November, between Hallowe'en and Yule.
Thanks to everybody who expressed interest last week. Same question: would you be likely to come if it were sometime in November? It seems less likely to be tied to any event except "the band and the organizers had the weekend free".