Playing sport at school, especially if you’re good at it, can be a brilliant escape from the drudgery of academia. But to be a girl who is interested in sport, it turns out, is less of a teamwork-building break from the classroom and more of a battle. According to Girlguiding, which is about to launch a campaign to make more school sports available to girls, only 43% of schoolgirls are offered the same sporting options as boys. Rugby, football and…