Factual error: Whenever Kim's phone rings during the first series, you can hear a polyphonic ring-tone yet she owns a Nokia 3315, which is a monophonic type.
99% Fat Free - S3-E8
Factual error: In 4.2, "Fame," Prue and Trude see Kath and Kel arrive at the awards, and act surprised they are together. However Prue and Trude have seen Kath and Kel together at their shop several times and laughed at their dress sense, etc. They also didn't know who Kel was before, and in this episode they do know his name.
Factual error: When Sharon is buying hen party accessories, the assistant asks if she's arranged beefcake. Sharon replies no, because Mrs. D (Kath)is a vegetarian. However Kath is often seen preparing chicken feet(in Old) and eating cocktail sausages in almost every episode.