I read this in the paper ages ago www.edp24.co.uk/content/edp24/news/story.aspx?brand=EDPOnline&category=News&tBrand=EDPOnline&tCategory=xDefault&itemid=NOED14%20Jul%202010%2020%3A05%3A12%3A573
The head put all the candidates through the same selection process and the best candidates were 2 girls for head girl, and 2 girls as deputies.
Interestingly the daily mail take on the story cites complaints from students as well as parents, which was not in the report linked above or the one I originally saw (I think it was in the metro).
The comments on the DM are pretty depressing, obviously, but interesting the take that this is "sexist" and the headmaster is "stupid" having picked a girl as head boy, as it were. They claim that this would never be allowed the other way around - really? Maybe they have a point - I struggle to think of any institutions with all men at the top....
Anyway thought you'd all be interested. Anotehr one where girls have done well, and the response is outrage.