Im having this exact same problem with my new fuel pump on the Bonus turbo, just cant seem to get the fuel pump banjo to seal, ive tried sanding the faces of the hose eyelet so that theyre flat and clean, fresh copper washers, tried fibre washers as these were fitted to my old pump before i took it off the road. And nothing, still pissing fuel all over the floor. Been messing around with it for almost 3 afternoons now too grrr!

Figured the eyelet or whatever it's called is out of shape/not square hence not sealing.
Im going to try this out now, if it doesn't work it look like its new hose time!

Cheers for the advice Tabetha