Revealing mistake: At the very beginning of the episode, Leonard Pearce is waiting for the cue for his character to start looking for his teeth. He's standing in the living room, between his room and Del and Rodney's room. (00:00:25)
Revealing mistake: When everyone's back at the flat, as Del Boy is looking straight down the hallway to his and Rodney's bedroom, someone comes up to him and he turns around. When it goes from his close-up to the wide shot of everyone else the shadow of the camera reversing backwards is visible for a few seconds.
Continuity mistake: In 'The Frog's Legacy' (1987), Del & Rodney learnt the story of Freddy The Frog for the first time - neither of them had ever heard of him before (Aunt Irene explains to Del who Freddy was. She mentions both 'Freddy The Frog' and his real name 'Frederick Robdal'. Del has heard of neither of these names). Yet in 'Sleepless in Peckham', it would seem that Del had known Freddy since he was 15. He even went on their first Jolly Boys' Outing with the rest of the gang.
Continuity mistake: When Del is proposing Slater a deal, Slater says "I don't like deals" and shoves Del's hand off the phone hook (Del was trying to stop Slater keeping him in custody overnight). But in the next shot Del's hand is still on the hook.
Visible crew/equipment: When Del and Rodney are sitting in the van after the auction you can't see into the back of the van for huge boxes. When they start shouting and screaming the camera angle changes to show the van rocking from a distance, and you can see someone in the back of the van through the back windows banging against the side of it.
Other mistake: Boycie asks to sleep in the Trotter's flat after being chucked out of his house and not allowed back in due to a gas leak. He states "I was going to check into a hotel, but I've left everything in the house; wallet, credit card, car keys, the lot... so all I've got is what I'm wearing." He isn't shown to be carrying any luggage. Later in the episode, Raquel complains that Boycie keeps putting on the hair gel that Del added onion puree to at the start of the episode. How was Boycie able to get his hair gel that was in his gas-filled house? One could propose that he asked the firefighters to receive it, but why wouldn't he also ask them to retrieve his wallet/credit card so that he can book into a hotel rather than sleeping on the sofa in the Trotter's overcrowded flat? (00:58:00 - 01:05:00)