Hi Paul!
Yes, I spoke to somebody who was on the programme and he said that they got an hour for each task, but they couldn't use the whole hour because for a lot of it the TV crew were setting up their own shots. For the first task, the hour was split between the two people who were photographing each other, so in theory they got 30 minutes each, but in reality more like 20 minutes. I think the setup on the Germaine Greer shoot was similar (which rather undermines Parr's claim that they got an hour-and-a-half each). I don't think I could have worked under those conditions.
It does make me wonder why Carolyn was spending so much time messing about with the teddy bear, if she only had 20 minutes. I think I would have just taken close-up face shots, although that's not normally my "thing".
I also learnt that they could choose to use either their own equipment or Nikon D80s. I guess most went with their own kit, given the preponderance of Canon straps and lenses I spotted, but this could explain why Carolyn complained that she couldn't work out how to get the exposure right when she was on Brighton beach. Cruel experience has taught me that, when you have just 20 minutes to get "that" photo, better the devil you know than some theoretically better piece of kit.
Some more info about why they may have got the contestants they did: I applied myself, but the procedure was pretty torturous. They only got the application forms online about a couple of weeks before submissions closed, and even then it didn't work with Firefox (they promised to fix this but never did, so I had to email in my photos in the end). Part of the submission was a rather personal longwinded and form, obviously designed to provided a detailed psychological profile so that the programme makers could choose a mix of people who might perhaps spark off some Big Brother-style breakdowns.
And, yes, you had to commit to devoting an entire month to the show.
Anyway, they confirmed receipt of my application, and that's as far as I got. I'm obviously not good reality TV fodder.