Diagnosing dishwasher “Check Water” LED. Bosch sms24aw01g

Hi,

Our dishwasher has stopped working. At the begining of a cycle the drain pump runs as normal. Then when the water should come into the machine not enough water is coming in and so the Check Water LED lights up.

Things I have done:
– checked the drain pipe under the sink, it’s clear.
– checked the water outlet under the sink and at the machine, both ends clear.
– tilted the machine back to see if there is water in the bottom activating some kind of flood switch. There isn’t.
– took the water inlet moulding off, where there are lots of channels the water runs through. It had some debris in it so I cleaned it out as best as I could. I don’t think this is the problem but I can’t be sure.
– checked the impeller water flow sensor spins, which it does.

Below is what I’m thinking of trying next but if anyone has any better ideas how to fix this I’d be grateful for some help.

I can’t find any video or guide on taking the machine apart further. Anyone know how to take the back off in particular?
Things I am thinking about doing:
– check the water outlet pipe where it connects to the machine (but water seems to be exiting the machine fine)
– replacing the inlet valve (I figure it may not be opening fully?)
– test the reed switch and solder on a new one if faulty (but I would imagine if faulty that would result in too much water not too little?)

Thanks
Charlie