This is Sidcot school in Somerset which is a Quaker establishment. My grandfather and his siblings and many distant cousins attended as students and my great-grandfather was a schoolmaster there.
In 1908, when the picture was taken, my great aunt would have been a pupil, but I don't think she is in this picture, or if she is, not at the front!
I can't think what they were doing was at all energetic!