Geomob is a London meetup of geo developers. Organised by Ed Freyfogle, it tends to attract interesting people like Gary Gale, Steve Chilton, Oliver O'Brien, Harry Wood. Mark Iliffe, Steven Feldman, Andrew Mackenzie.
One of the talks was was by Angharad Stone from the Environment Agency about how they are opening up data.
Another talk was from Richard Fairhurst about cycle routing from OpenStreetMap and Ordnance Survey data. This included some details of how he used OS-RM and OSM to map DECC data on how busy roads are.