Continuity mistake: In the scene where Neville is telling Dennis he should find a woman, Dennis is getting dressed up in his suit to meet Dagmar. After Neville has finished talking, Dennis leaves the hut without a suitcase. But when he arrives at the hotel with Dagmar he is seen putting his case on the bed(Dagmar has one as well). It is clear that he has come straight from the hut, as he is telling Dagmar what Neville had told him before he left.
Continuity mistake: In series 1 episode 10 (Last Rites) when Oz asks Bomber if he is interested in his porn deal, just before Bomber gets his foot broken, he tells Oz he has five kids. In series 3 episode 5, Bomber tells Lainie (the native American girl) when she asks if he has any family, that he has four children. Is not likely that any of the kids have died as he has just told her his wife had died and would probably have mentioned the loss of a child as well.
Plot hole: In the first series, Bomber mentions 'City's my team', referring to Bristol City, and dislikes the other Bristol based football club (Rovers). If this is the case, why is he wearing the distictive blue-and-white quartered shirt of Bristol Rovers in series 4? I know that people change allegiances, but it's very unlikely.
Continuity mistake: When Oz and Moxey are in the supermarket loading the trolley up with beer, the camera angle changes to a close-up on Moxey then when it returns to Oz, more beer has been removed from the shelves. You can't hear any cans being moved when the camera is on Moxey and there is the same amount of beer in the trolley.