"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]