Children's TV - and a plea

I have vast swathes of recollections of things I used to watch when I was younger (not to mention books!). CITV generally ruled, although we did watch some CBBC - and that's aside from the indomitable collection of Disney videos. (Breakfast TV, normally filled with cartoons - although that included Pokemon - was strictly limited to holidays)
When I was younger - Thomas the Tank Engine, Bodger and Badger, Noddy, Old Bear, Sooty, Dennis the Menace, Winnie the Pooh (ohh, great cartoons those were). Probably the greatest show, which definitely stands up to rewatching, The Animals of Farthing Wood, and similarly the perfect Mr Bean. Goosebumps, Sabrina the Teenage Witch, Hey Arnold, hazy memories of the ultra scary Blair-Witch style Jeopardy and Are You Afraid of the Dark. Sunday evening dramas like Aquilla, the oft-mentioned (in my family) Black Hearts in Battersea and The Wolves of Willoughby Chase, The Phoenix and the Carpet, and something involving chocolate. The Worst Witch, The Demon Headmaster - based on the books, with a creepy series about plants and cloning too - Children's Ward (a soap, basically). My Parents are Aliens, Jungle Run, Art Attack, Zzzap!. The original, far inferior, Horrible Histories. And also lots of pretty good shows about computer games - which seems odd now, looking back.

And then there's a drama series, which must have been shown around 2002-2003, which I can't for the life of me track down. And of course, I remember a lot about it - albeit not its strange, weird name that you could hardly pronounce (an acronym, perhaps).
It was presented as a game show or reality show, and had a group of about eight children (who were slightly annoying and bickering) staying in "the world's largest film set". A bit like The Truman Show then - weird things happened each week, shot on 'hidden' cameras, but we were given a glimpse of what was happening behind the scenes - stuntmen and actors and people moving the set around.
I think I missed the first episode (it was on twice a week, Mondays and Tuesdays I think, about 4.30 - I used to scour TV listings even when I was younger), but there was a cake competition I remember, which ended up being poisoned and making the entire town ill, and the villagers angry. In another episode, the group ate some drugged blackberries, and then woke up to find the entire set had been switched to the medieval times, in a sort of time travel adventure. In another, the group stood outside a TV shop, when suddenly aliens attacked (at night - so basically just lights and explosions) and random bystanders were seemingly killed in front of them.
Of course, this made an impression on me - but I can't find anything about it online at all. At the end of the series, the group of children that remained won a prize, a huge money prize (a million dollars?) but couldn't spend it until they were older. It's probably an American or Canadian or Australian show or something, which is why I can't find it.

Around the time of this mysterious show they were syndicating lots of similar dramas from other countries. Pirate Islands was good, set on a virtual tropical island with an over-the-top pirate captain's ship parked nearby. Blake Holsey High looked cool, of a similar style to Buffy, but I only saw the first few episodes. Alongside more home-grown stuff - Sir Gadabout and Harry and the Wrinklies, and odd stuff like Don't Eat the Neighbours.

Later I moved to BBC for some reason - watching Blue Peter for once (though I can't remember many others - though Shoebox Zoo was good, and later things like Trapped!) and then, when I was about 13, Doctor Who would have arrived! And it was long overdue...