Your child's education is about much more than free childminding.
What you need to do is qualify as a teacher and then teach a full timetable with all associated duties, from marking work (in your 'own time'), having to supervise children at break times, being the first point of contact for issues ranging from chaotic parenting to personal injuries, dealing with bleating parents who want their child minded for free but not to take any responsibility for it's behaviour, attitude or lack of homework.
Then you might get an insight into why the UK school year is as it is. The pace both for teachers and pupils could not be kept up for 52 weeks of the year. The holidays are part of an agreed pattern. Five additional training were forced into the holiday provision by the Tories in the 1980's, but even they could see a dangerous precedent. The teaching profession would drop them tomorrow if given the chance.
Tell you what, send junior to a private school. Oh my! They have EVEN LONGER holidays. Move to Europe. Yes - you got it - far longer school holidays.
I agree that having to pay for childcare is a burden, but that is not the creation of schools and teachers.