Stephen McCole

It has been confirmed that Steven Mccole will play a guest star in Series 5. Whether this is a recurring role or an appearance exclusive only to one or two episodes is currently unknown. Steven has worked with director Justin Molotnikov, who will be directing the first three episodes, in the past. Steven also said 'scripts are great', which indicates hints he be appearing in more than one episode.

Source

 * http://gealach-ros.livejournal.com/712809.html