[Shaun]

oh and I didn't address it in the OP because it was getting very wordy, but the basic different between 'group' and 'band' is:

Groups: Sugababes, G.R.L., Westlife, 1D, Little Mix, The Vamps
Bands: Arctic Monkeys, Mumford and Sons, Arcade Fire, The Black Keys, Death Grips

so basically 'pop' and 'other'... it got confusing last year with acts like Disclosure/AlunaGeorge because they're pop but they write their own stuff... so for acts like that i'd put under 'group'