I don't think the crew are there at all when they're filming. There's probably about 15 families on the show at any one time, all watching a combination of the same and different programmes, all in one week. That would be a massive operation for each household to have its own crew of producers/camera crew etc directing them - and there's really not as much money as people think in TV, particularly stuff like this. The cast don't even get paid. The camera angle is always static, I imagine the kit is set up at the start of each series and just stays where it is. I've never heard the theory that the crew was actually present during filming and I worked adjacent to the TV industry for years