Gloucester's scrum had been dominant all game, but in the 63rd minute the Blues turned the tables and from close range Powell powered forward and Nicky Robinson followed up to break Barkley's tackle and score under the posts for their bonus-point try.
The government has long argued that including a wide range of qualifications as GCSE equivalents in the tables can create "perverse incentives" for schools to offer lower quality qualifications.
However, experts in the field warn that perhaps even more so than with the equivalent league tables for traditional MBAs, the ranking should be treated with caution given the huge range of options on offer.