Disconnect the return line where it joins the metal pipe at bulkhead , plug the netal line with a short bit of hose with a bolt in it.
Get a sealey or similar ( engine oil suction pump) and connect it to the return line , switch ignition on to open shut off valve and then suck fuel through the pipe work .
Once it comes all the way through you will still have to crank engine a bit to get fuel up through injector lines aay 30-40 seconds but it will start.