Explore Learning was founded in 2001 by Bill Mills, a Cambridge maths graduate, and now has 139 centres around the country (plus five in Texas run by a sister company). They are located mainly in shopping centres, so busy parents can get on with their weekly shop while their offspring perfect their times tables, punctuation and grammar. Most of the children, who are aged four to 14, come at least a couple of times a week – the membership allows for up to nine sessions a month. Saturday and Sunday afternoons are the busiest times in the Bradford branch, which has 290 children on its books. The tutor-tutee ratio is one to six, but the tutors are not usually qualified teachers; they may be students or mothers returning to the workplace. All trained in the teaching materials and behaviour management.

https://www.theguardian.com/education/2018/dec/05/an-education-arms-race-inside-the-ultra-competitive-world-of-private-tutoring