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.
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: Near the beginning of the episode, when Del talks about his Polaroid, there are no extras walking behind him. The shot changes quickly to Rodney, then to a wide shot of both Rodney and Del in which time the 2 extras walking in front of Vimmal have manages to walk down the stairs behind them. (00:02:30)