Yes, the first night was excellent with very clear image, good lighting and only the occasional camera mistake.
The surround mix made such a difference from flat stereo and really made it all so engaging and involving. The BBC do seem to mix 5.1 very well with no exaggerated surrounds and yet give a good depth to the soundstage. The coughers were picked up very accurately.
The sub managed to pick up a few odd bumps and thumps which were not part of the music. I often think the BBC loudspeaker monitoring is not going as low as it should in the sub department as I hear bad rumbles and thumps quite often, yet in Jools Holland's show there isn't enough bottom end.
The big mistake is that HD and surround don't feature in any of the BBC proms pages, at least from my searches anyway. All they list is broadcast schedules for BBC1, BBC2 and BBC4. No sign of BBC HD or any HD broadcasts and nothing about surround. They are certainly keeping it a secret. It can't be still experimental as they managed it well in the 2010 season.
I worked with the BBC surround department in 2003 and had a DTS surround CD of an earlier prom (Holst's Planet Suite) it was excellent but has now been lost.