My friend turned up at 1330, she couldnt cope with "mooching" around from 1000 like i always do. She decided at about 3pm, after buying an Alien related t-shirt that she wanted it signed by John Hurt. We wandered to his line and got a ticket with 624 printed on it. After an hour or two, which allowed me more time to admire Dame Diana & swoon over Jane Wiedlin , we returned to the queue. My friend got her T - Shirt signed, got a pic with John Hurt and we even had time to attend his talk.
I think this may have been luck as he was pretty busy, but my two friends are "virgins" to all this and despite their apprehensions genuinely had a good day. Too be honest, as others have said, if you really want to see someone you just have to keep a check on the line number and sometimes be cheeky.