christ on abike thats a lot of wires on them ISO thigmys.
Had a better rummage and the purple is live all the time and is 2.5mm2 so pretty hefty. Theres also a white with orange which according to my haynes wiring drawing is for the radio. It goes live at ignition 1 and 2. It's also very thin I wouldn't think it would power a fart let alone a decent wireless.
Cant I just power it with the purple so my radio works all the time, not with the keys? The worst that can happen is i'll leave the radio on, flatten the battery and die horribly in some godforsaken desert.