Episode #4.3 - S4-E4
Revealing mistake: When Janice is speaking to Johnny by the pool, it is pouring down with rain. Look at all the parasols/walls etc in the background and you can see the sun shining on everything. The rain is artificial rain.
Episode #4.1 - S4-E2
Continuity mistake: When we first see Gavin and Kenneth, Kenneth is holding a fork with nothing on it. In the next shot, a sausage has appeared on the fork. (00:05:25)
Episode #4.6 - S4-E7
Continuity mistake: When Jacqueline, Gavin and Kenneth meet Sir Henry to find him listening to his iPod, Jacqueline, Gavin and Kenneth are all looking at each other. In the next shot, the three are all looking at the Sir Henry.
Episode #4.4 - S4-E5
Other mistake: During the scenes in the Hawaiian Function Room you can see the sun shining down on the floor and furniture, when it's meant to be thundery with heavy rain outside.
Episode #4.3 - S4-E4
Continuity mistake: At the end of the scene where Pauline is talking to Michael at the bar, Pauline puts an empty glass on the bar and says "keep them coming". Mateo picks the glass up, and puts it under the bar. In the next shot, the glass appears back on the bar side.
Episode #4.1 - S4-E2
Visible crew/equipment: When the Garveys get out of the car and walk up the steps you can see a camera man and his mic in the wing mirror of the car if you look closely.