During the "taxi ride home" scenes, members of the public can be seen staring into the back of the taxi when David is doing his piece to camera. Not technically a mistake as this is "reality television", it's nevertheless an indication that they could see the filming taking place inside.
Although this edition largely returns to just one person at a time talking to camera between meals, there is a scene with Paul and Jane together in the same room giving their opinions on Sarah's food.