First of all, I added a little bit more
information to the post on the cast -- some of the people whose parts aren't listed are accounted for, though not all of them. (I got the extra stuff from IMDB and twitter.)
Secondly, there's a London 2012
promo clip on the BBC site with a few clips -- some shots of the duel!fail, Henry and Mowbray laying their hands on Richard's sword, and a few lines of Richard's confrontation with Gaunt (PATRICK STEWART OMG). I am going to guess that the cuts/pacing is an effect of chopping for the promo and not the way the scene plays out in the actual production, so that you may all mock me if I am wrong.