Thanks all - I’m no stranger to making up and bending brake pipes - I must do 40-50 per year on average. I’ve had one of these for over 20 years now, and couldn’t live without it:
https://www.sykes-pickavant.com/products/braking-tools/pipe-flaring-tools/63
I also have a hand-held one for flaring pipes in situ. I only ever use Automec cunifer and agree it’s wonderful stuff. I tend to favour steel fittings over brass, which can deform quite a bit where they engage with the flare, but that’s a personal choice. However, apart from the occasional reservoir pipe, I’ve not done a whole car in 1/4" - only ever 3/16", hence my worry about bending. I also don’t have all the original pipework, as the car wasn’t complete - and the body is on and painted, which will make things a bit trickier, but not impossible as the system must have been designed to be serviced in situ.
Following on from Rob’s comments, does the 140 have a mix of sizes too? If so, will Viart be my friend here - or the factory parts book? Or, indeed, this forum?