Richard D North, the one person who had volunteered to Tony Newbery details about the BBC/CMEP seminar of 26 Jan 2006 as early as Dec 2008, has published some remarks about 28Gate in a comment at his site:
I have just caught up with [28Gate]. [...]
I haven’t quite worked out why the BBC were so keen to keep private the list of participants to the seminar. It may not be sinister or stupid. I am fairly sure that I feel some scruple toward any publication of details of “Chatham House” seminars. I know that one mustn’t ascribe particular remarks to particular participants. And, actually, I don’t think I have ever named the participants at such a gig. I would be inclined to check that they were OK with being named before I did so.
I am pleased that nothing I have heard about the seminar contradicts what I did recall and say about it. I did find the event quite depressing and I was peeved that the possibility of my helping to introducing the BBC and its audiences to all sorts of interesting ways of thinking rationally about climate change were not advanced by my attendance. I did think and did say that reporting on climate change would improve as broadcasters realised that their audiences did not want to do very much about it. I think that has come to pass.