i can smell petrol fumes inside car...

Hi all,
I am running a Golf GTI Cabrio 1989, I can smell petrol in the car.
However, nothing seems to be leaking outside, checked underneath car nothing leaking and no smell outside. Only when you get in the car, you can smell the petrol.

I have noticed also that i am putting slightly more petrol in the tank than usual.
Also smell gets stronger especially when i put petrol in tank.

Any ideas where smell could come from?
Fuel filter cap is shut beneath rear seats.

cheers

couple of straight forward places to check.

1. fuel gauge sender area (work outside and be carefull, no sparks )
  remove the back seat base and you will see a black cover plate.
  remove screws and lift this, check the seal on the cover plate is in one piece and good condition.
  Check for signs of fuel in the sender plate, is so check the fuel pipes to sender connections are tight. Replace with jubilee clips if in doubt. dont forget which way round they are connected, one is return one is send.
   finally on this one loosen fuel gauge sender, and check gasket, see if its been twisted or just perished. New gasket available from VW direct couple of moths back and only a few quid. So you may wish to replace any how. If you put a new one on then lubricate a little so doesnt twist/kink.

2. fuel filler neck
   Check the fuel filler neck for any signs of bubbling on the inside. Even with the slightest ammount would indicate filler neck perished so I would personally replace.

Thanks djheap22
will check that later today and let you know.