Flaring brake line

Hey guys, I have a rear flexy line stuck onto a flare nut and the flare snapper has rounded it and vice grips ain't doing nothing for me. It's annoying as all hell cause every single one up till the prop valve and MC came off but just not this freaking one.

Anyways, I think best safest choice is to cut it and put another flare nut on and re flare. But the issue is that I know absolutely no one with a flare tool that's capable of a double flare.

Firstly, what size is the line exactly? (car is 1995 EG civic)

Secondly and most importantly, anyone in Brisbane own one and willing to help out?? As I said it's only 1 line, Itl take like <5mins.