Brake Fluid for LBCs

Back in the old days, we were always told to use only English brake fluid
because the seals were made of natural rubber instead of vulcanized rubber.
Is that true for a 1976 Midget? I checked the manual and found nothing about
what kind of fluid to use. It just says "approved" brake fluid. The master
cylinder cap says DOT 3.
If so, can you name a brand? Girling? Lockheed? Castrol?

TIA,
Kent
1960 Bugeye
1976 Midget
Future old fart in an old car!