I did a couple of them when I was 16/17, at the Lumb Bank centre.
Mine may have been slightly different, as we were all competition winners, but we had a great time! They were poetry focussed, and everyone was between 16 and 20, just as background.
Each time, we had two resident poets (the judges of the competition, who we'd all actually heard of), and a visiting poet. The resident poets lived with us the entire week, ate with us and were around for general inspiration/discussion. We were set exercises, went through poems one-to-one with the residents, and had a workshop with the visiting poet. We also made an anthology, and did a mini poetry reading. Plus, plenty of time and space to write on our own, and a great little poetry library.
One of the best experiences of my life, honestly.