Strong Fuel Smell - Blacktop 4AGE

[WAMACK1]

Hi Guys

I have completed a Blacktop 4AGE conversion into my MK1 Cortina and am very happy with it. However there is quite a strong fuel smell inside the cabin when driving.

I have a Carter black lift pump to a 2L surge tank and a Bosch 044 fuel pump with a return line to the fuel tank. As much as possible I have aluminium fuel lines with rubber hose only for connections.
The car is old but in good condition, i have sealed up as many of the holes in the firewall as I can

Any theories on what might be causing this fuel smell issue?