Revealing mistake: When Del sees Denzil skating along and tells him that he's got his money (the butterfly), Denzil gives him a high five and crushes the butterfly. If you look at Del's hand when Denzil goes past him, you can see the butterfly is not crushed at all.
A Slow Bus to Chingford - S1-E5
Visible crew/equipment: When Del says to Rodney atop the bus about Janice not wearing a bra, a stage light is reflected in Del's drink. (00:25:10)
Revealing mistake: When towing the car, the tow rope is slack, showing the van is not towing the other car. (00:05:45)
Watching the Girls Go By - S4-E6
Revealing mistake: At the start, Mickey Pearce is playing darts in the pub by Boycie. On the 3rd dart, he actually aims for the floor behind Boycie to make it seem like the dart bounced off the board. (00:01:10)
Revealing mistake: When Rodney is asking Del if he thinks the bathroom is haunted, you can see stage lights in his spoon. (00:10:20)
Yuppy Love - S6-E1
Continuity mistake: The text on Rodney's computer keeps changing at the start with no one touching the computer. (00:03:15 - 00:10:50)
Chain Gang - S6-E3
Continuity mistake: When you see Rodney and Albert in the van, a woman walks past but in the next shot(a long shot of the van), the woman has disappeared.
Visible crew/equipment: As Rodney is coming round a corner while being chased, if you look carefully, you can see that the driver is a stunt driver and the passenger is a dummy.
Visible crew/equipment: When Rodney and Del are back in their own flat, Del is pouring a drink, the shadow of a boom mic can be seen on Rodney's shoulder right up until Rodney walks away.
Continuity mistake: When Del is escaping in the van, there is a view from the side of the van and the door is almost completely shut. But in the next shot, which is a direct view of the back of the van, the door is wide open, allowing space for the toy dogs to fall out of the suitcase and onto the road. (00:03:45)
The Russians Are Coming - S1-E6
Continuity mistake: At the start of the episode when Del say 'a butcher or chemist' Rodney is looking straight forwards. In the next shot he is looking at Del. (00:01:30)
Visible crew/equipment: When Del walks in to the flat, as he answers Grandad's first question, the shadow of a boom mic can be seen moving behind him on the blue front door. (00:04:15)
Video Nasty - S5-E5
Continuity mistake: When Mickey Pearce is filming, Rodney walks in and says something, then turns and walks back into the kitchen. When the video is shown at the Nag's Head, Rodney turns the other way before walking out.
Revealing mistake: When Raquel walks into the living room after Rodney has told Del about the successful bloke, you can see a studio light on one of the pictures on the wall.
Visible crew/equipment: When Rodney and Nerys are being chased, as they go over a hill, you can see the ramp the van goes up to get the height.
The Jolly Boys' Outing - S6-E7
Continuity mistake: There is an ash tray behind Rodney and Albert's bed. In some shots it is there and in some shots it isn't.
Revealing mistake: When the kid steals the orange, look how the orange is conveniently placed higher than the rest to make it easier for him to pick up.
The Russians Are Coming - S1-E6
Visible crew/equipment: When Rodney says that the country isn't prepared for war, a boom mic shadow can be seen on the sofa as Rodney walks past it. (00:05:35)
Modern Men - S8-E2
Revealing mistake: When Del and his mates are in the pub, when it's Del's turn for the drinks, he gives Mike a hairdryer (really an electric paint stripper). If you notice, Del picks up the hairdryer off the floor.
Chosen answer: An apparent long string of illnesses.