okay, so engine all rebuilt which turned out great, so just replacing the loom and tried to go for a simple no battery loom... bought this one off SIP...

https://www.sip-scootershop.com/en/product/wiring-loom-217897-vespa-px80-200e-lusso_86100000

...but just ignored the "w/o horn rectifier" which I probably should've looked into a bit more? maybe?

So ran the loom, changed stator over from 5 wire to 2 wire, I can see that indicator switch is different, uses a later model switch, 6 wire instead of 3 wire and also the ignition barrel is a 2 wire instead of the 6 wire installed as standard.

So all that is okay as I'll just get a new ignition barrel and indicator switch, my question is about the horn, so there's only the one yellow wire coming from the switch, is it just a matter of hooking into a 12V source coming from the regulator and having that feed into the horn?
stock 200 with GS piston, SITO plus pipe, everything else standard
stock 200 with GS piston, SITO plus pipe, everything else standard