Thanks DD that's what I was hoping to hear but not at the same time.

Yeah when I hold the key it just keeps spinning so that's why I was only doing it momentarily as I heard it is bad to run it unloaded. plus I was trying to show it working randomly. I also did a continuous test during one of the times it caught the engine with the ignition disconnected. After 10 or so seconds of cranking it started spinning. It feels like it may turn back a touch but it is hard to tell, I will check again. The video is quiet but you can turn your sound up if possible as the engine is the loudest noise.

Yeah the solenoid wasn't firing at the tyre shop due to dirty connections on the solenoid and a loose - battery connection I believe. It works fine now, every time.

So a bad bendix drive can sometimes work? but will fail totally eventually yeah? Maybe de-greasing it was a bad idea