"Mate" is a Strine (see LetStalkStrine) word, loosely synonymous with but with utterly different baggage than the American "sir" or "man". MateShip is a trust relationship. Mates are not necessarily friends, but they expect one another to act with tolerance, compassion, and good humor. "We're mates" means we've mutually taken the piss (PissTake) until we agree we're on a peered social footing.
I heard that "raggae" is actually patois for "regular" (clearer if you can pronounce the french "regulier"). "Mahn" is distinct from "man". As for "sir", well, what do I know ... I worked for my rank. [google Joseph Conrad on male bonding]