Please keep us updated on how you get on. I've had a rubbish time trying to diagnose this, and am still no further on.
As others have said, it's the airbag warning light. If you do the light reset procedure with your key, you can put the car into diagnostic mode. The light will then flash at a different rate, indicating the fault code. Unfortunately the way mine flashes just indicates "some fault", and not a specific one. I've connected to a diagnostic machine, and the fault keeps moving between the driver's steering wheel, and the passenger front airbag (not the seats). A new spiral cable is a common fix, but despite putting a new one in, I had no joy! Still flashing shortly after doing the reset.