http://www.channel4.com/info/press/programme-information/are-you-autistic
I don't have access to 4OD or any way of watching a recording, but thank you both anyway! I guess most people nowadays do have access to these things. My TV might actually record things into itself, I'm sure I remember something about that in the sales spiel, but I wouldn't have any idea how to make it do half the things it's probably capable of. Sorry!
Incidentally, I did manage to find out (eventually) online that the programme is repeated at 1.55am on Friday 30th March on Channel 4 - if anyone else misses it!