Used this for a majority of the injection fuel lines on the Caterham

www.thinkauto.com/tfe.htm

Its not a particular pleasure to fit and is quite hard to handle. The ends are easy enough to fit in a vice but out of a vice they are a bit of a pain.

Best method to cut is cover with tape and cut through the SS cover. Then cut the PTFE liner with a stanley blade.

Have plenty of band aids at the ready, the SS covering takes no prisoners.

Thanks, I'll pass that on.

I think the boaties understandably like the idea of an off the -shelf hose that fits rather than making something up, and if your sources statement that

"On racing vehicles, this has lead to the universal usage of smooth bore PTFE (Teflon Ž ) hose with normally a stainless steel."(My bolding for emphasis)

is accurate, that should mean that if they use "quality" stuff sold for racing, they should be OK, even though its not sold for use with hot mineral oil.

Flexible pipes in braking systems are lined with EPDM rubber which resists brake fluid.

EPDM is not to be used for mineral oils.

www.manuf-rubber.com/news/what-you-need-to-know-ab.../

I'm sure you are right, and thanks for the link.

Its slightly odd that they don't list brake hoses as one of the applications, given the properties

"The automotive industry uses radiator and heater hoses, window and door seals, wire and cable connectors and insulators, diaphragms, and weather stripping."

but I think I've confirmed that adequately elsewhere

https://www.hosequip.co.uk/epdm-brake-hose-75mm-x-13mm-1962-p.asp

for example