Miele G975SC

I went to this dishwasher today which has not been used since july, when you push the on/off button the drain/ inlet light comes on, when you select a programme and push the start button the light flashes and starts to fill for a couple of seconds and then stops filling and the light stays on, this will continue all the time until the machine overfills. i have checked all pipes for blockages but can find no fault i suspect the air break or fill reed switch but would like a second opinion and hopefully some part numbers. many tahnks Andy