Have you got a scooby or an ST?
The filler neck is hard to come by a used part apparently so I'm assuming it might be common?

I was getting the smell inside the car like when I've stopped at lights or a junction because I usually have the window down.
Also, when my lambda was knackered it was using massive amounts of fuel and the emissions were sky high and there was no strong exhaust fumes then.
So, in my experience petrol smell = leak