Fuel hose or pipe?
 

It would be a lot easier for me to use hose for the fuel delivery line (rear tank to front engine) but does it have to be metal pipe/tube to be IVA compliant?
I can't find anything concerning this in the test requirements or the forum's knowledge base.

You can use metal pipework to get the fuel around, the requirements are stated in the IVA document for fuel hose but metal pipework e.g. galv steel should be fine, some suppliers now do hardline systems such as speedflow and goodridge. Just look at what most manufacturers use, 3/8th or 5/16th bore galvanised tube or copper nickel pipe similar to brake line pipe, if you have a local classic car builder around then pay them a visit and see what they use and whether you can buy some off them, otherwise it's places like Holden Vintage and Classic or Speedflow

Thanks for the speedy response.
Once the fuel pipes are in and the reverse gear (for the R1 engine) is operational, I can order the bodyshell, can't wait!