All Available Season All Season Specials Sep, 2010 2 episodes 0.0 Series 1 Sep, 2011 6 episodes 7.4 Series 2 Oct, 2012 6 episodes 7.8 Series 3 Feb, 2014 6 episodes 7.0 Series 4 Mar, 2015 6 episodes 8.6 Series 5 Aug, 2016 6 episodes 8.5
