Communication Problems (a.k.a. Theft) - S2-E1
Plot hole: Basil torments Mrs. Richards by miming when he is speaking to her, so she will think her hearing aid has failed. However, she speaks twice during the scene, and she would hear herself - obviously - and would know that he was trying to fool her.
Plot hole: "Sight Unseen": Wells has the key to Lori's shackles. Weston, who knows this, knocks Wells out, but instead of taking his keys, uses a completely unnecessary (and considerably more difficult) set of bolt cutters to break the leg cuffs. (00:32:30)
Plot hole: During "the changes" people fear machinery, but the woman who pulls back her curtains to watch Nicky and the sikhs go past is wearing a watch.