They were all at Cambridge together, and it said that Richard discovered Roger cheating in exams and reported him to "The Dean".
Cambridge University does not have a "Dean".
Most of the individual colleges have a Dean, but this is a religious position, essentially a chaplain.
A bell rings 3 times in the background which usually signifies the time but the clock on the wall says 9.30 when they are in the police station. Around the 40min mark.
Two times, Dwayne says Humphrey fell out of the window. But he didn't; he fell over the railing at the edge of the deck.