Yes, "turniphead", and he looked so innocent about it, like "what's the big deal, his head looks like a turnip so that's what I'm going to call him until you get around to giving him a name".

The three hours is American; i.e., including time for commercials. So the episode on the 18th will air from 8:00 - 9:00 p.m., and the episode on the 25th will be 8:00 - 10:00 p.m.

They've shown three seasons of MI-5 here. Are you just starting with the first season now?