Andy, it's not a T5 thing. Every P/PX/T5 even with an autolube came like this in our part of the world. The choke lever tube is 6mm in diameter. The cable wire goes through the "Lever Spring" and attaches to the choke lever. Cable end stops on the "Lever Spring". And the "Spring Cotter Pin" creates friction on the choke lever so it stays open when you pull it. Made a diagram. This is as best I can describe it...
The ON - OFF sticker came from SIP. They also have a RES - ON - OFF for the old fuel taps. The "PIAGGIO & C" sticker is actually red & silver but it looks like gold due to the reflection of the yellow...










































