Planet Earth was a mix of everything. 35mm, 16mm and some HD. I never did find out if it was shot 24fps or 25fps, though I still suspect the latter as it was probably post produced in 25fps/25p.

I'm fairly sure Warner will be doing the encoding on BBCs behalf, which should hopefully mean a good VC1 job. The US release is getting Attenborough's narration though - at least I seem to recall that being mentioned in the press release.