I've had a student record a beatbox performance at the last minute. It doesn't mention beatbox anywhere specifically on the spec but it does say "an individual performance is defined as one person playing/singing/maintaining an independent melodic/rhythmic part" which covers it as far as I'm concerned. "It also says N.B. this includes ‘rapping’ in all of its forms" which from their old-ass perspective might include Beatbox. Anyway, it's too late now !