Peter
I had some hassle connecting the unleaded neck to the tank as well. There appeared to no concept of alignment at all.
I dd start down the flexible rubber path and ended up with a short length of 2" marine exhaust tube that could handle the fuel but was about as flexible as 750mL bottle of
VB. I persisted with it for a short while but ... eventually looked for an alternative.
With no facilities to fabricate the connection myself, I made up a template (from 3/4" flatbar) for what I needed, sketched a diagram and had it made. I ended up with this:
Cheers
Geof