Finally, months after writing the third-ish draft of the half-hour pilot episode, I've received some useful feedback from one of the people I sent it to. My friend who is a Famous English Comedian writes:
"A storyline where Graham puts a webcam in a girl's bedroom and then wanks at the end might be a bit pervy as a pilot episode."
He's absolutely right; Graham does sound a bit like a monster when the story is summed up like that. In the script I'd tried to balance it so that the audience would at times feel sorry for him, but maybe I didn't pull it off.
The Famous Comedian also offered some valuable advice about the editing of Graham's dialogue, which I'll take into account when I write an entirely new pilot episode with a totally different, hopefully-acceptable-to-TV-execs storyline.