Bosch garden shredder (MK45 Ampthill)

Hoping someone might be able to do something with this. Otherwise taking it to the tip for recycling.
Motor works perfectly and blades in good condition but safety cut out keeps activating as soon as you turn it on. I’ve taken it apart and tried to fix the mechanism. Can’t see anything broken or wrong with it though.
Knob to remove cover is broken but still works.