If you could smell it in the car through the air vents then its likely it was coming from the engine bay.
On our 16v's theres a tank vent valve near the airbox that clicks intermittently, when it does this it vents the fuel vapour/fumes into the throttle body via a black plastic pipe.
What I noticed on my car was that this pipe was rubbing on the AC pipe near the driver's side turrent and was wearing the AC pipe down a bit (the metal one!) as well as the vent pipe. Worth a look just to see if theres a hole... if you have A/C
Generally mine clicks intermittently on cold start over a period of 5-10mins of driving.
