I've now found out some of the colours of the wires on the K1200RS, and probably many others in the BMW range.
(first colour is main colour, second is the thin stripe colour)
Brown (thick-ish) - Earth
Grey/Black - Tail/back (red) light
Grey/Yellow - Brake light
Blue/Red - Left indicator/trafficator
Blue/Black - Right indicator/trafficator
In addition these were to what I believe is the alarm socket (under seat left-side about half way back)
Red - probably perminant live feed
Green - (live) probably something to do with ignition
So, based on the above, I wired my Autocom into the tail/back light feed so it's power is off when I leave the bike, but will only come on when the side lights, at least, are turned on. Tested it with by girlfriend last night and all works well.