Throughout the episode, Cassie has bare feet at all times, even when outside. Yet when Simon and Cassie return to Perry's studio to talk to Teal, she suddenly has slippers on her feet.
Throughout the episode, Simon Templar has a black thumb nail on his right hand, presumably due to a prior accident. When he is looking through Vogler's desk near the end of the episode, you can see this. However when a close up is shown as he examines the tapes, neither thumbnail has the blemish.
When the 'sculpture' is carried out of the studio and into the van, it clearly isn't filled with anything; it sounds very hollow and two men can move it without any difficulty.