SOW: BOB is no addon.
It was first planned to be a further addon for IL2, then it was decided to create the Battle of Britain as first theater of war for a completely new engine: Storm of War.
It's been in development just short over 2 years, now, and it has not been officially announced by a distributor. So you won't find it on UBI-Sites and/or Maddox Games.
For the same reason news are a bit thin, though you can find a lot of screenshots and some videos of certain features of the new game and a couple of interviews and Q&As.
Be sure to check out these threads for further details:
http://forum.1cpublishing.eu/showthr...?t=2040&page=1
http://forum.1cpublishing.eu/showthread.php?t=6909