The Navy and the Air Force also have Bands. You have got yourself really confused. Even before CAMUS, Corps of Drums etc were trained teeth arm soldiers with a secondary function of beating a bit of pig hide in one form or another, same goes for buglers and pipers although there is a certain amount of skill in playing the Pipes. The bands are made up of skilled and qualified musicians whose primary role is to play music.If units can have Pipes and Drums (which is still a band) why do we need a Corps of Music?
I'm sure if the RN or RAF had the option of 800 personel they would be happy with that uplift.
However, how the hell the AAC got a band leaves me confused as hell.