There are a variety of fittings needed, depending on what you're plumbing up
From left to right: These are Brass and Rubbish, stay away from these (Local suppliers seem to only be able to offer them), Next, these are the original Oz Style ones as found in the rear subframe, Next are the same as previous, but new from the UK, Next is the M10 type for the Tandem M/Cs and Last is the 3/8 UNF ones that cover most of the car.
Before we go too far on fittings, considering tubing used for Brake Lines and Making off of the flared ends, there's some slang terms floating about and these can make for some confusion when taking about them. The BMC / Leyland / Rover factories in the UK and Australia had a standard for these, CT-1 and CT-4. These were to SAE Standards J512 and J513. When referring to the type of flares used in a particular Brake Line application, these are the terms I prefer to use as there's some over-lap and gaps in the various slang terms I've heard over the years.
SAE J512 here;-
https://www.sae.org/...Tr9CB2LTUf98M9Z
NOTE the terms used there is Double Flare and Inverted Flare
It is possible that BMC / Leyland plants in other countries used different standards for the brake line fittings of the vehicles they assembled. All I can suggest here is to use some care in checking however these days 99% or more of the replacement parts come from the UK, so the SAE Standards would apply to them.
All countries have standards to which various Automotive Components need to be manufactured or tested or assembled to. Brakes of course have a standard. In all countries throughout the world, where it comes to brake lines and the type of flares they have, while the standard for the shape and size may vary between them, ie SAE, JIN, DIN etc, they all agree that the flares must be a minimum of (to use the SAE term) double flared, here's an extract from the Australian Standard LG for them;-
SAE J1047 supersedes J513, however the terminology is the same, this has just been broadened to include metric and a few other standards.
Note the term used here is double flared.
There's two basic types of flares used on Minis and Mokes.
First and most common on the vehicles is a Double Flare (BMC Standard CT-1).
Double Flare to SAE J512 and it's cross sectional appearance.
The other type of flare is the Inverted Flare (BMC Standard CT-4)
Inverted Flare to SAE J512 and it's cross sectional appearance.
The Inverted Flare is accepted under various vehicle standards as the flare is formed by having 2 folds formed in the tubing.
This is the double flare, usually used with the M10 and the 3/8" UNF Tube nut (last two on the right above)
Generally fitted in to something like this;-
This is an Invert Flare, as used with the hoses on the rear trailing arm, the Female Tube Nuts (first 3 from left above) are used with these;-
Fitted on to these