Rumour has it that he won the half a million pounds and that Channel 4 aren't showing it yet because they'll lose viewers and nobody will want to watch the show anymore as all the excitement will be gone!
When Noel was on Jonathon Ross recently he did say that there had been a couple of winners but they weren't going to be shown. I wonderd at the time if he was joking or really serious. I haven't been keeping track of players but if, as you say, someone has "disappeared" it sound feasible.
It seems a bit daft not to show them if it's true! It hasn't done Who wants to be a Millionaire any harm. I do like the show but it's on far too much now. It was novel at first but getting boring now.
If it is true their 'logic' is self-defeating. People watch the show to see if someone does win the �250,000. If they are prevented from doing that then what's the point of watching it?