So the horn hasn't been working... couldn't work it out.
There was some additional horn in the engine bay near the airbox that was tapped into the horn loom. Think it may have been done for the alarm. Otherwise someone could disconnect the horns by reaching under the bumper.
I looked in the Haynes manual at the wiring diagram and saw the horn circuit is pretty simple. It basically just grounds out to sound the horns. I also found this diagram on the web.
I removed the additional aftermarket horn, reconnected both horns at the front, removed the additional loom that was aftermarket.
Still wouldn't work... then I decided I'd swap the relay out from HS30 00150..
But it made no difference. I knew the horns worked because when the alarm was installed and I reconnected them, they went off..
So that lead me to believe there was an issue on the switch side.
After a bit of faffing about, I removed the cowling around the wheel. Then I noticed the horn was working? I thought maybe I jiggled a wire and checked all the connections.
Then I put the cowl back on and the horn stopped working. Perplexed I realised there was a loose wire (see photo).
It looked like rather than solder the joint, someone had tried ti silicone it in place... anyway, I soldered it back so it's nice and secure and the horn now works. Success.. I had to remove the steering wheel to get to it properly though.
I'm sure the neighbours were wondering why the hell the horn kept going off, but this was the last non-working road worthy item I knew would come up.
Other items not working are interior courtesy light (which I think is the bulb), 1 reverse light is out (probably bulb) and the antenna switch doesn't work (or antenna doesn't go up and down).