Boeing and Airbus recommend what's simple and design it for the lowest common denominator. There aren't many lowest common denominator airlines in the UK. If the manufacturers raise no technical objection to a variation from their SOPs then what's the beef? BA have shown it works perfectly well and the only two screwed up RTOs I personally know of in BA were both inititiated by the captain.
Incidentally, if you are heads in on the T/O roll and the handling FO spots an imminent runway incursion ahead of you would you prefer him to shout "stop" or try to explain what he's seen so you can make the decision?