Petrol Smell in car

Hi everyone,

I'm wondering if anyone has had the same problem as me and has any sort of answer for me!
About a week ago, my fiesta started smelling really strongly of petrol. I first noticed it when I got in the car for work in the morning. It went away when I started driving so I thought it may have just been because it was a bit chillier that morning. Well fast forward a week and every single time I get into the car after it's been off, it stinks of petrol. When you start driving, it goes away.
I replaced my fuel cap, that wasn't the culprit. So I got a local mechanic to come check it out, he couldn't find a single thing wrong with it. No holes in my fuel tank, fuel lines seem fine, exhaust seems fine, there's no wet patches on the ground... yet it still stinks!
The car drives absolutely fine. No difference at all. There's no engine management light, no lights on the dash at all. Can anyone think of what it could be?
I feel like we've checked everything but we are obviously missing something if it's still smelling of petrol.
It's a really strong smell of petrol too, you really have to air the car out before getting in.

The car is a 2007, Fiesta Ghia, 1.4L, petrol, manual.

Thank you in advance

This could be from a grommet seal - the rear gas filler neck - rests in a cradle - it has grommet to seal and support the filler neck.

IF the grommet is sheared or cracked - it is very likely that a weep hole used to let fuel and it's foam, is not letting the fuel drip cleanly away. Instead - it leaves itself on that ring of the filler neck. So with the age of the vehicle it may have finally eroded the grommet to let fumes from the tank to start to seep in - you'd know this by inspecting the neck, grabbing the neck and try to move it up down or side to side - if it moves, the grommet and or neck and the filler cap and seal - need to be replaced.

It's can also indicate that your seal for the fuel pump - located in the rear frame rise support, under the bottom rear passenger seat cushion - may have rusted and its now venting air and since the canister is also by that tank - might be a signal to have the EVAP lines and the system inspected.

Thank you for your reply! I feel as though it may be the first point you made. I paid it no mind but upon re-fueling a few weeks ago I felt as though I couldn't get the fuel nozzle to sit correctly within the hole, it kept moving about but felt fine afterwards so I just ignored it. I, for some reason, didn't even think of this being an issue haha. Thank you again, I'm popping it along to the garage tomorrow and I'll let them know of this.