Just like the title says, my vw passat (2007 diesel) starts and works fine, just as normal, except there are no dash lights and none of the dials work. Every other light in the car seems working. Also, when I turn the ignition to start the engine, the lights and dials come on for a second and then disappear.

Two possible clues (or not)

1. the car was valeted today however the company says that it must be coincidence and there is nothing that they could have done to have caused it
2. One of the head lights bulb was gone for a few days, I have replaced it today but it made no difference to the dashboard lights/dials


Any ideas what could it be and where I should look?