This is the next in the most recent 7th Doctor Trilogy.  Black and White finally goes into why we have been having references to the TARDIS being White in some stories, and Black in others.  As mentioned in my review of Protect and Survive, Black and White deals with threads...

Protect and Survive is the beginning of the latest 7th Doctor Trilogy from Big Finish.  Not only is this the start of a trilogy of adventures, but it answers the question, why there have been references to the TARDIS being White and then Black in various 7th Doctor...