Here's the link.
http://news.bbc.co.uk/1/hi/uk/7401826.stm
Boys still making up c.80% of crime for 11-17 year olds. I think I get the bit about there being more girls - it'll be about the ratio of boys/girls nationally, think traditionally more boys born each year something like ratio of boys 51:49 girls but more girls survive infancy and so globally around about 49:51 ratio boys/girls. I have an inkling that infant births ratio now favouring girls.
However, suspect it is more to do with a shift in attitude towards bad behaviour in girls as well as drink-fuelled violence ... although shoplifting got a mention!