Composer Lorne Balfe confirms that he's written and is recording the score for "The war between the land and the sea"

Balfe has a load of high visibility (audibility?) credits to his name, dating back to his time as an assistant to Hans Zimmer. The standout title for me is another Bad Wolf production, His dark materials, but YMMV — it's a long list of movies, video games and TV shows he has scored.

I think it's interesting that Murray Gold wasn't chosen to do the honours, as he has with most of NuWho and at least parts of its Torchwood and Sarah Jane adventures spinoffs. It certainly indicates that the show may have a different flavour than the main show.