Bosch Classixx Condenser Tumble Dryer – Clean Light

Hi, looking to understand a little more about how this dryer type would light the clean filter light and stop the machine.

To be clear – I’m not talking about it stopping because it thinks the container is full of water (I’ve aware of the whole ‘hidden flap’ thing and that part of the dryer is working fine)..

In our case, its stopping because it thinks the lint filter needs a clean. I’ve cleaned the entire machine out, including the hidden flap area, the condenor, all internal pathways that I can reach. I’ve also had the back off and cleaned the heating element, however nothing has done the trick.
I’m thinking that whatever sensor is in operation must be some kind of air flow sensor, but I can’t find it anywhere in the parts diagrams.

I have found the sensor under the lint filter (I believe it’s an NTC sensor) and cleaned that in case that was the one, but again – nothing has worked.

Anyone got any suggestions where I should be looking to understand more about what’s happening?