Back in 69, when I started, there was a chambers that took, as members, only Balliol men who had a first in law . I only know this because they took a friend of mine who had a first from Cambridge, and this did only after much soul searching before allowing such a break from tradition; good heavens, the fellow isn't even an Oxonian!. Had he been a she, they would certainly not have taken such a candidate, Balliol or not.
Remember too, that starting at the Bar then invariably needed some financial support because you'd be living on what you earned and that was sometimes scant and always late in being paid. Significantly, it was the highest earning sets in commercial, tax, and Chancery (yes, Barmaid, don't laugh) that were first to offer what amounted to a salary from chambers funds to help youngsters when they started.