Hi I'm a member of a Sci fi/fantasy club in Melbourne that's actually the second oldest Sci fi club in the world, started in the shadows of post WWII and NO I wasn't one of the founding fathers OR mothers...
I'd be amazed if there wasn't several fan clubs in London along similar lines.
Here's a link to one of the so-called Meeetup Groups started by people in London (we have several in Melbourne of this nature).
http://scifi.meetup.com/100/
There's also a Sci Fi/Fantasy film festival that's been running since 2002 in london, looks like this years has already gone but here's a link that may prove handy for next year's events:
http://www.sci-fi-london.com/
Hope this helps..
