Fuel smell - Rear quarter outside car.
 

I've brimmed the tank for the first time in ages and noticed a raw fuel smell around the rear quarter of the car, strongest under the wheel arch.

At first I though it was the fuel filler cap not being closed but even when fully (clicking) tightened the smell remains. A corroded fuel filler pipe also makes sense but....... the tank appears to holds pressure e.g. I get a pressure release when I open the filler cap so how can the filler pipe be leaking fuel if it's airtight?

Anybody got any ideas what could leak fuel (vapour) only when tank is over 1/2 full but not affect the air tightness of the tank?

The carbon canister is located around there, so that could have something to do with it.

I’ll have to work out where that is on the Legacy, I know the bugeye one ended up in the bin! Looks like it’s the other side of the car so most likely the fuel pump/filter or the filler but I’m still confused as the tank clearly holds air pressure as when I release the cap I get the hiss of air!