After much wrangling by Steve Virgin to bring together interested parties, and much editing work by a team at BBC Bristol, given freely in their spare time, a short promo of the Bristol public lecture is now online, with the full 50-minute cut to appear in future:
http://commons.wikimedia.org/wiki/File:Jimmy_Wales_Bristol_Public_Lecture_wp...
There is a slight issue with interlacing. I will try to fix that with future attempts at transcoding to Theora. It's difficult to achieve archival quality while also keeping under the 100MB upload limit.
Is there a Wikimedia UK YouTube channel we can issue this through? If not, do we want there to be one?