We have an Indesit WIDL 126 washer drier which developed a similar problem, except that we had two flashing LEDs + the door lock LED.
The combination of LEDs that flash indicates what is at fault with the machine. If you phone Indesit, they probably won't diagnose the problem over the phone but will offer to send an engineer. The engineer looked up what the combination of flashing LEDs meant on his laptop and quickly fixed the problem. Unfortunately, this cost us £70 call out but only £6 for the part (in our case, a pressure switch which detects hom much water has been taken in by the machine).
If you know a friendly washing machine engineer who can replace the pressure switch to see if that's the problem, it might save you the call-out charge from Indesit.
Steve
June 2006