The yanks call that kind of dialogue "As you know, Bob..." dialogue. Because it's used (not so much nowdays in tv shows where the episode begins and one character says to the other "As you know, Bob, the inertial dampeners are failing and we can't get out of the orbit of that sun!"

http://www.tkkenyon.com/fiction-writing-exposition.html

*shudder*

Excellent post, as always.