Petter A1 magneto strip down

Hi, I posted question a while ago about issues with my Petter A1 wipac magneto, and was advised that there was an issue with the spring mechanism and advised to strip, which I have now done. Please see the attached, it looks like there should be 2 "arms" which engage in a clutch like mechanism via a spring, but as you can see from the image there is just one. Not sure where the other could have gone because there is no evidence that it has been stripped recently, indeed one of the weight pins was brazed in!
The drawings one member kindly sent me do not show this mechanism, so I guess slightly different model, can anyone advise if I should have 2 such arms? If so what are they correctly called, so I can attempt to source replacement (or make one!).

I have searched for video of magneto rebuild, could anyone point me in direction of video, or drawing?

Thank you for your continued support