Episode Four - S2-E4
Factual error: The BBC One channel ident introducing the Six o'clock News is a real one, featuring swimming hippos, but in real life such a comical ident would never be used before a news bulletin.
Episode Six - S3-E6
Factual error: Dave and Nessa's wedding is meant to be on 13th June and at the end supposedly 6 months later Nessa, Gavin and Stacey are sat on the sea wall in beautiful sunshine in summery clothes when it should be middle of December.