I think the problem is that if you don't plug the banjo, and run the return hose (where the cigar hose is) to the return valve; You will get some veg rests in the diesel filter. Because the returned fuel is passing the diesel filter... And when you place the filter before the lift pump it will become under vacuum and therefore suck fuel from the return line.

Atleast I had trouble bleeding air with low level on the tank. And from what I heard the return line is about 1/4 fromt he bottom. I managed to bleed air when i filled 20L diesel on the tank so it became about half full.

hehe thats about 1/3 of the price I pay in norway!!! And wvo is not that common here, so free flow on the oil!