The point ORAC is, I believe making is (and I'm inclined to agree)...
Are the 'phase 1 criteria' for tabbing around Brecon job-spec criteria for physical fitness, or for mental toughness. If the latter then adjust away to achieve an equivalency. I would, however, say if the former then I have to agree with the mob. However, I'd hazard a guess and say none of us are experts in the SF selection process, so how's about we let them make their own professional decisions and trust them to make the right one to enable warfighting to take place in the safest way for our own side and the most dangerous for her majesty's enemies.