Smelling of Fuel

Since driving my car home from its service and a few local runs (probably totalling around 60-70 miles) I’m getting quite a strong smell of fuel which I think is coming from the drivers side, with the window open, not inside the cabin with the window closed.

I can’t see anything obvious in the engine compartment that would be causing this. Does anyone know of any fuel related components that could have been disturbed during the change of the rocker cover gasket and/or the aux belt tensioner assembly? I’m thinking fuel breather pipe or pipework near to the injection fuel rail?

I did fill the car up with fuel on the way home, but it hasn’t overfilled or spilled anywhere and the smell does seem to be persistent when driving.

Not smelling fuel with the windows shut and within the cabin tells me its not directly in the engine compartment. With the window open and smelling fuel, i would say its related the the fuel filler section.
But, like most things in these cars, like finding creaks and rattles, its hard to know where things are coming from. Leave the car parked up and have a thorough look round inside and under the engine compartment. Then run the engine and do the same. Also, remove the undertray and put cardboard under the car overnight, see if anything is dripping.