The De Vere Village Urban ResortElstree’s Centennial Park
7th July 2013 - 10am to 6pm.
The JGSGB is a national organization with close-to-a-thousand members. Their announcement of the event says that "as well as offering its unrivaled expertise in Jewish immigration, settlement, naming patterns and genealogy, it has access to extensive sources, including exclusive online databases" Its website will also give you membership information, regional Jewish genealogy groups to consult and publications to order. Their journal is called Shemot.
The 1st JGSGB Family History Fair is supported by ancestry.com, familysearch.org, findmypast.co.uk. myheritage.com and the London Jewish Cultural Council.
If I was going to be in London, I would attend with a smile on my face.