Wire colours for horn button coming off the clockspring (2009 Jimny)

So my Jimny failed MOT on no horn.

15A fuse is good (and hazard lights it shares with work)
2 wires onto the horn. Black with grey stripes gives 12.4v to the battery positive terminal, so I assume thats a good earth. What I then assume is the live wire is white with grey stripes.
If I connect the black wire to the horn, and wire the 2nd terminal direct to the battery positive the horn works.
No airbag light on so I'm desperately hoping it's not the clockspring but I want to check what is flowing and in and out on the horn circuit.
Anyone know what colour the wires are going to the clockspring so I can multimeter them? I can see 2 chunky white wires going to the clockspring/ignition/indicator unit (with a blue line, and a green line) but they look too chunky for 15A.

I have the service manual, I didn't realise there was a supplementary wiring manual, that I don't have. Worse case, can I get get onto any official Suzuki docs site for a few quid for a quick look?

And of course, any other suggestions of what to look at?
 

I'll answer my own question in case it helps anyone in future. It's a single blue cable with red stripe that comes off the clockspring and goes to a relay behind the under dash fuse box.

Does point to the clockspring, but I'll take the airbag off and check the switch first. Still seems odd to me the air bag light is OK.