As many of you parents may have already learned, the UK school system is a bit different to the US. I think my wife and I have had to learn as much about school as our children.
Our oldest (11) is on his way to secondary school (middle school/high school) next year. While he is entitled to go to any of the State Schools in the area, they're not the best, which forced us to look outside our area. Luckily there are several with excellent track records within easy travelling distance, but all are highly competitive.
All required entrance exams. The schools will tell you not to bother with tutors, as the tests are really a guide to see how well your child will cope with the schools curriculum. Don't believe a word of it. The real test for a child is the taking of the test. At this age most haven't had to deal with testing on this level and it is a skill. Sadly not one that is taught in school. A good tutor will help your child pace him or her self and develop a sense of confidence in dealing with time and pressure.
Our son found none of the tests painful but all a challenge. The biggest being the time constraints. There's a great deal to cover in a very short time. Had it not been for the tutor he would not have gotten in to the wonderful school he will start next year.
The tutor will also be able to answer allot of your questions regarding the system, it's pitfalls and how best to proceed.
