Thats the water softener unit. Water flows through the brown crystals to soften the water as it fills. During the cycle salt is fed back in to the crystals to regenerate them. If you are using all in one cleaners and not putting salt in the water softener it pretty much becomes...
If it's like the Hoover/Candy lifters there's a screw holding it. On them you can get to the screw with the machine on its back and the sump hose removed. The heating element is in the way but just about doable through the element. Having said that the screw might not be accessible that close to...
It's the alternating water distributor. Switches the water feed to top and bottom spray arms.
Put your enr number into the search box on the Neff uk spares website and take a look.
You have most likely got a fractured drum support arm, only noticeable with a heavy or uneven load accompanied by a heavy thumping.
The inner tub would have to come out and be split in half to extract the drum. If you look in the drum from the front you can see the shape of the spider through...
On the highest scale of my test meter, 2000k ohms the valve coils read approx. 5 ohms. You will need to disconnect the wiring to the valves to access the terminals.
(What i noticed when it has the issue is it fills from the prewash compartment but never switches to fill from the main detergent compartment (which i think is does when its working properly) as thecycle goes to zero.)
It's possible one of the dual inlet valve coils is open circuit, do you have...
It sounds as though you have a leak that is triggering the anti flood and making the pump run. Most Miele washing machines have a solid base and an anti flood switch like dishwashers. Pull the machine out and tip it back the water in the base should spill out. Then find the possible leak.
The main power board is back bottom right, the mains cable plugs in to it. If you can get it out and inspect it for the power chip and resistor failure that the Neff,Bosch, Siemens dishwashers comonly have.