What fuel line fits this pump assembly?

As per the pictures, does anyone know what the fuel line connector looks like that fits to the internal hex?
Mine are the quick release connectors and this pump is a used replacement I've just bought so I will need to buy new.
Any help appreciated.

Thanks
Nigel

 

I opened the casing which I should have done before I started this thread and found that the internal hex is blank.
Am I right in saying that the hose tail is the feed and there is no return port but rather that the feed tees off inside the pump housing and incorporates the pressure regulator?