OMG, that's one heap of trouble for the 10 year olds!!
Half the country were looking for them!
Although it's maybe a bit silly to say it now, I did think the child sounded older when I first played the audio clip and suspected a hoax, as they answered the handler's questions very definitely. My DS is 3, and i don't think he would have understood the question about the letter or the window so readily, for example.
But then i listened again and thought "no, I'm being cynical, the voice does sound like a little one".