yeah, pretty bad access. I couldn't see the hose from the helm seat nor the quarter berth. But we probably don't have to see it.
If it was me, I'd first take off the fill fitting and see if the hose will pull out of the hole. Might not, given the hose clamps.
If it does, attach the new hose to the old one and pull out. If hose too stiff, use sender line.
If that won't work, remove the teak trim at the foot of the quarter berth. The shelf has to come out, too. There's a bulkhead back there under the teak, but I can't remember if it goes all the way to the top. Worth a try for access to the upper hose clamps.
If nothing else works, an inspection port could be installed in the cockpit bulkhead under the fill fitting.