What is a reliable accreditation to look for in British business schools?
I am not sure how valuable accreditations are. I would suggest going by reputation rather than a binary is/isn't accredited. I think it would be rare for a school to have a "good" reputation, but lack critical accreditations. There likely is variability in the accreditations that schools with questionable reputations have. I would still base my decision on reputation and then only when deciding between a few schools with very similar reputations give any weight to accreditation. As for finding out about reputation word of mouth, league tables (e.g., the Guradian tables), and the RAE are reasonable starting points.