Tunnel lines are a real pain to do, but not technically difficult. Lots of notes here on Pelican to guide you. I can email you with notes I have if you like.
Before you jump off the deep end, check the hose that is leaking. Are you sure it is a new hose and not the original cut shorter & slipped over the new Banjo?
I can provide a new 15 in length of Multi-Fuel hose w Banjo as above and you can make the repair yourself. I can also do a M-F hose w M14 Female for the return to the tank. You MUST drain the tank to do any of the above. There are also alternative hose clamps as Porsche has used for many years. They have a continuous band inside to keep the teeth from cutting into the hose. In my opinion, for field use the Oetiker clamps are still the best.
Len