More details are emerging
There are more details on the BBC site, including pictures of the three main actors, Natalie Dormer, Shaun Evans and Aneurin Barnard.
http://www.bbc.co.uk/mediacentre/proginfo/2015/33/the-scandalous-lady-w
Here is the trailer I saw yesterday.
https://www.youtube.com/watch?v=X4qy1MJ4pEY