They struggled to fill the last series with content, how on earth are they going to fill 20 episodes?
What attracts the majority of the audience for these programmes is the characters, the human stories, rather than any great variety of situations that those individuals find themselves in. Throw in a few different locations and some interesting technology - along with no small element of schadenfreude - and you've got yourself a TV format. The fact that the programmes seem repetitive because the same, or very similar, scenarios keep cropping up doesn't really matter as long as the audience can relate to - or at least have some kind of emotional response to - the characters you feature. (I think we have to accept that the fact that we're on this forum puts is in a rather different group from the typical Channel 5 target audience!)
Mark does state 20, 1 hour long episodes but that does seem very excessive!
At least partly down to cost. It's an awful lot cheaper to film 20 episodes in one go than, say, as four series of five. They don't even have to show them as one series, they could easily schedule two blocks of ten, one six and two sevens, or four lots of five, for example.
