[Stuart]

Planet Earth’s Blu-ray release has the BBC HD ident on all of the discs. Still looks good today, although the HD novelty has long worn off. They’d definitely stopped using this by around 2009 if other BBC Blu-ray’s are anything to go by.

I have the 2010 reissue of Planet Earth and it has the BBC Earth ident instead (which I think was very new at the time).

That's because BBC Earth is more than just a channel, it's a brand they use across all media platforms and interactive experiences at museums and theme parks for anything related to their Natural History material.