Most of us should know that this series had a pilot episode that did not air in most markets mainly because two different actors portrayed the roles of Mitchell and Annie (Guy Flanagan and Andrea Riseborough). Eventually, they were recast by Aidan Turner and Lenora Crichlow and paired with Russell Tovey, who remained as George after that episode to insure viewers would be familiar with this trio as the stars of the show. For those who are curious, or have never seen the pilot, I found this link that will enable you to finally check for yourselves: http://stagevu.com/video/vfiiiqkhuwus
Among the things to notice here are that Annie was portrayed by a Caucasian actress, Herrick, originally by an African-British actor (Adrian Lester), and George's ex-fiance was named Julia (portrayed by Claire Foy), which was the same name used for Josh's ex in SyFy's version. Unlike the latter, things did not turn out tragic for that Julia when she discovered George's secret. I felt these actors did a decent job, but Aidan Turner and Lenora Crishlow were the better choices for their respective roles, but I liked Adrian Lester better as Herrick. If it were up to me, I would have kept him.
Since we're between seasons of Being Human, this would be a good opportunity to view this pilot episode. I should caution though that this link provides a version with French subtitles. But you should be able to follow through with what was going on here. Hope you enjoy it!