I'm in the north east tutoring science and get fully booked up right from September, every year since 2008. I am a full time teacher as well though so I don't do many slots. Amazingly, most of my students come from the local prestigious independent school. I worked with over 50% of their A-level Biology cohort one year. I think their preferences for staff with PhDs and research portfolios in their field rather than teaching qualifications leaves a lot to be desired.