Simplest solution is to do a Google search for "Indesit WIE 147 is locked into demo mode"
I did that and found this within 60 seconds:
Demo Mode
If the machine is on Demo mode 'D on' will be displayed and the machine will NOT function.
To reset the machine for normal use:·
* Turn the power off at the wall.
* Push in and hold down the Start/Stop and the Start/Reset buttons, while still holding down, turn the machine on at the wall.
* 'D off' will be displayed and the machine will function normally.
Anon, September 2016