Boy, would I have looked like a fool if I had sent that email to Ring, I just did a test and the horn button position, whether before or after the ditch light button, didn't matter.
Graham,
Let's work through this methodologically.
I'll post some not so great photo's along the way.
As posted earlier, you must use this button
for the horn and the Ditch light (flashing) function button must be before any buttons that turn the ditch lights on.
The ditch light (flashing) function button must be set up to the correct function wires the ditchlights are connected to.
In the photo of the ditch light button setup below, I have the ditch light function in slot 12, indicated by the slot coloured green. I have the button to turn the ditch lights on individually in slots 13 and 14. They are wired to the green wire and purple wire respectively. Note the setup of the button. You must use the exact button picture for this to work.
On one the advanced setup screens, you must enable the "Auto Ditch Lights on Horn" function. I don't know if this the same setup screen on the HC-1 as the HC-2. If you haven't enabled this function you'll need to.
Hopefully, this will get you up and flashing when you sound the horn.
- Tim