Never heard of that question before and never seen it mentioned in sales information. I always thought it was just the pipe size that was important.
All the brake system on the TR7 is metric so presumably its the ISO/DIN Been making my own for donkeys years and recently bought a used BluePoint kit TF5A on Ebay and that works just fine.
Some of the cheap ones don't always do such a good job.
update, I found this information after a bit of searching but none of the adverts selling fittings that I have seen mention the differences. http://racetrackdriving.com/tech/brake- ... ed-bubble/