Outer door fault - CR02 Washing machine circa 2003/4?

Please someone help me!! I have a Dyson washing machine CRO2, it must be around 7 or 8 years old now and never really had a problem with it. However now I have a problem where the digital display is telling me to close the outer door and no matter how many times I close the door it still seems to think the door is open? I have tried the reset by switching off and holding the soil/temp buttons etc but nothing seems to work. Anybody any ideas before I reluctantly spend the £££'s on an engineer...boohoo so close to christmas too :'(