Bosch SRS43C12GB constantly draining

Folks, hope someone can assist me. My Bosch SRS43C12GB is constantly draining, and I *think* I’ve ruled out the usual suspects. Thanks to the help of this forum, Im starting to figure out how these dam things work but still cant locate the problem.

Issue:
When the machine is powered on, the sound of a motor running can be heard constantly, as well as the occasional clicking of a relay. The washer never fills with water or starts cleaning. Same after attempting a reset, or on any program. The base was full of water inititally, but I’ve cleared this out and the problem remains.
Diags:
Tipped machine on its side – water did start to come out. After many, many hours, found all the fiendishly hidden torx screws and got into the mechanism.
Cleaned out the water in the base.
Anti-floor polystyrene float is down
Actuator arm for this is fully down
Red can type float in the matrix is fully down
The arm between the red can and the polystyrene float moves freely, and is down. The anti-flood microswitch moves freely, and will click on/off (confirmed with multimeter), and is in the down position.

I’ve confirmed the sound of the motor I can hear is the drain pump
If I fill the machine with water from the kettle, it will drain successfully, I can see the water flow through the matrix and it seems to drain normally, but the motor doesnt shut off and the program doesn’t start. Looking inside the machine, the drain plug is clear and free of obstructions.

Is there maybe another device triggering the anti-flood mechanism that I’m not aware of, as all the ones I’ve found on this forum don’t seem to be tripped, it seems to drain properly when there is water, unyet its stuck like this.

Edit: If it isn’t the anti flood mechanism, is there a sensor that indicates when the washer has emptied so it will start filling again? I’m wondering if this may be blocked or obstructed?

(Hopefully the answer isnt “call an engineer”, I’ve spent far too long figuring this thing out to chuck in the towel now!)