Nope, there's a section on the bbc licensing website about it and you don't have to have the licence for non-live tv, iplayer included.
Also, a bbc licence checker who checked my friend who also has no licence but watched iplayer on their laptop, told them that was fine as long as they didn't watch the live stuff.

I found the behind the scenes stuff so amazing. I watched the making of Attenborough's Life, and wow... the scene where he's on the sand dunes with the sea coming in, they were so close to not being able to make the shot because the sea was coming in so fast.

It makes it so much more interesting.
Like that Saharan camel train, where they were showing the little hot air balloon thingie (can't remember the name), and how difficult it was to get the shots because the camels all wandered off at night hehe.

And the actic one with the Narwhal hunting! Wow!

So very cool, it really adds a lot to the series.