Fifty-Fifty - S1-E3
Factual error: It doesn't make sense that Daniel would be researching classical music, or that he chooses Jen as his 'phone a friend' because of her apparent knowledge on the subject, because there are no topic categories on 'Who Wants To Be A Millionaire' - the questions are entirely random, Daniel would have no way of knowing one of the questions he'd be asked would be about a particular topic.
Suggested correction: That's exactly why he was studying classical music, he didn't know what topics would be covered and he wanted to have a good knowledge of various topics. Since Jen appeared more knowledgeable in classical music than he did, he wanted her to be one of his phone-a-friend in case he came across a classical music question that stumped him. At the time, a contestant pre-arranged with producers 3 friends to be considered as a phone-a-friend. Daniel undoubtedly had 2 other friends or relatives that had greater knowledge on other topics than he did.
There's no way Daniel just happened to be studying classical music and seemingly nothing else, he didn't ask Jen about any other subject, the episode implied that Daniel was studying classical music as though it was a dead cert that a question would appear. This wouldn't be the case with Millionaire.
He would if he knew that classical music was an area he was particularly bad in. For example I would study as much American history as possible because it's my worst subject. But I'd also have my husband as a lifeline because he happens to be a history buff. It makes sense that Daniel would have Jen as one of his three lifelines if it seems that she's an expert at something he's awful in. Presumably his other two lifelines are knowledgeable in other strategic areas as well.
The Red Door - S1-E4
Factual error: Richmond says that the song "Coffin Fodder" is track 4 on the Cradle Of Filth album that he gives as a gift at the funeral. In reality, it is track 9.
