While I don't have access to specific episode information like "Gently - 2009," I can tell you the main actors and actresses who appeared in the series:
* Martin Shaw as Inspector George Gently
* Lee Ingleby as Detective Sergeant John Bacchus
* Lisa Greenwood as Barbara (Gently's wife)
The series also had a recurring cast of characters, including:
* Peter Davison as Detective Chief Superintendent John Bacchus
* Patrick Malahide as Chief Superintendent Arnold Brightman
* Shaun Dingwall as Detective Inspector Harry "Mac" MacDonald
* Alex Jennings as Dr. Robert Forrest
To find out which actors appeared in a specific episode, you would need to look it up on a website that provides episode information, such as IMDb or Wikipedia.