The current regular meeting place for the London BiblioGoths is:

The Castle,
34-35 Cowcross Street,
London
EC1M 6DB
If you come out of Farringdon tube station and look left, The Castle is right in front of you.

For the past four or five years we have met roughly once a month, almost always on a Sunday at around 14:00, and meetings have usually lasted around three hours. I see no reason why this will change in the near future...