Here's one way to watch it; if you have chrome, download the media hint extension from here
https://mediahint.com/ and then you can go to
http://www.bbc.co.uk/iplayer/search?q=africa which will allow you to stream it online. enjoy!
edit; the first one isn't working at the moment. If you do watch them, be sure to click the "watch in hd" link under the video, it's a game changer