Another issue is that any wiring diagram or schematic is subject to copyright so no one should be publishing them on the Internet anyway. As far as I know there are no official repair manuals and schematics for UK washing machines and other appliances readily available.
Providing water level indication eg, by using a dishwasher pressure switch to activate LEDs or lights to indicate the water level in a tank. By using two dishwasher switches and adjusting their individual set-points, it's easy to have six levels indicated. However, you'll need a lot of wires to connect the switches to your display.