Neff H7860 Microwave - How do you turn the beep off?

This is an excellent microwave oven but I would like to shoot the technician who decided to make it beep a total of 48 times over a period of 30 seconds at the end of each heating. Whenever we use it there is a rush to the oven to hit the Off button as soon as the countdown timer reaches zero to stop the infuriating beeps!

A recent internet forum post suggested that pressing the Start button for 6 seconds would solve this. Unfortunately that doesn't work with this particular model. Any help would be much appreciated. Thanks.