Other mistake: Cook and Effy manage to fall through Pandora's Mum's wardrobe, into the next door neighbor's bedroom. But this is not possible as the neighbors' houses are detached.
Other mistake: When Hannah/Belle is talking to her "agent" you can see the escort website and Belle's "Enjoy List", a list of acts she is willing to perform, on the agent's computer, however some of the items on that list are mistakes. 1) She has (pardon the language) "cum in mouth" marked with an x for no; but has snowballing marked with a check for yes (you can only see half of it but it is a checkmark not an X). This is a contradiction because snowballing involves "cum in mouth". 2) She has a no marked for "moresomes" yet she does "moresome" as evidenced by the foursome in Episode 7. 3) Belle is so concerned over someone discovering her profession that she worries in the first episode the escort website's pictures aren't pixellated enough to conceal her identity; yet she has both being photographed and being filmed marked as yes.
Episode Four - S1-E4
Other mistake: Jake is sitting at the kitchen counter top and is watching TV whilst doing his homework. You can see his red pencil case labelled 'Jake Rowlings'. Many times throughout the series the parents have been recognised as Mr and Mrs Brockman - not Rowlings. The children also have been referred to as Karen Ben and Jake Brockman. (00:13:40)
Suggested correction: Throughout the series, the Brockmans (specifically Pete and Sue) seem very ashamed of their family. In the first episode they tell Jake to give people Grandad's address. It doesn't seem out of character at all for them to tell Jake to give people a false surname. Also, Harry Potter came out at the same time so Rowling would be a very easy surname to choose. This isn't out of character for the parents at all if you look at the rest of the series.
The family's surname is not mentioned (other than on the pencil case) at any point in the first series. Likewise, the grandad is not named in the first series either. Sue even says she doesn't know anyone called Frank Morrison during Series 1 when Pete mentions a colleague of that name. This creates continuity errors when the family are given the name Brockman and Sue's father is established to be called Frank Morrison from Series 2 onwards.
Hard Bargain - S1-E9
Other mistake: When one of the kidnappers knocks on Michael's door, it shows him undoing a sliding barrel bolt before opening it, but the bolt does not have anything it slides into on the door frame rendering it pointless, especially as the door opens inwards. (00:30:20)
Mona Lisa's Revenge (1) - S3-E10
Other mistake: Mr. Smith scans the Mona Lisa and determines that it is genuine from DaVinci's brush strokes. He should have also noticed the words "This is a fake" written in felt tip under the paint, from when The Doctor replaced the Mona Lisa with one of DaVinci's "forgeries" in "City of Death."
Other mistake: During the concert, the drummer's hands don't follow the music playing.