Proud2 tickets are £25 extra (you have to have a Drupalcon London ticket already to get one - edit your purchase and then continue to get the option to buy one). I hope there are drinks or something included as otherwise £25 to stand in an (admittedly nice-looking room) from 8pm to 11pm only seems a bit steep. Anthony - can you explain?
The Drupal London community organises regular general Drupal events, events focusing on specific sectors or user cases, and takes part in various trade shows.
The Drupal Drop In user group events have been held regularly since 2006 and are a great place to watch presentations on new modules and techniques, put your questions to the experts, and network with the rest of the community.
Drupal Focus events are half day conferences with presentations, discussions, and networking about specific sectors such as Education, Publishing, Government or topics such as Media Handling, Theming, and Maintenance.