The headmaster changed two years ago since then the school has gone down hill.
Thats not THE reason to think about Mall twice. Mall is prep school, it goes up to 13. All secondary schools take the majority of the children at the age of 11. You don't have the option of leaving mall at 11. School does not prepare your child to leave at 11, far fewer places are available at 13 and school life between year 5-8 isn't great. Kids are under constant pressure due to entrance exams and then common entrance in year 8. The focus is exams from year 6 onwards and not on any real learning.
I have seen kids who have left Mall at the age of 11 do much better in other schools and happier. If passing exams is the goal for you child, go for Mall is the best. If you want you are looking for a happy child and quality education think again.