As far as I can tell, this pipe is now completely unavailable. Has anyone fabricated a replacement, either in copper or nylon/plastic?

See my earlier thread:
Fuel Pipe Connectors

In the states the fuel line material is hanging on the wall at the common auto parts store with a tool kit to barrow to fabricate your own . The manufacture may have a website for customer questions and fittings . Hope this get's you some traction ( pun intended ) as you get a line on your repair . Are you the Andy Bracket man ?

Mooooo , Parker