I have a feeling that TIPSY, our resident oracle, will post in due course, and take you under her wing.
This is for Independent (fee paying schools) and exists at 11+ and also 13+.
Scholarship exams are sat at a different time on largely the same syllabus, but at a higher level.
Just to add to the confusion, many of the top schools set their own scholarship exams, which kids sit at yet another time.
It is probably useful to focus on broadly what type of school you want, and then look at how you need to get there.
1. Buy a copy of the Good Schools Guide either in print, or on/line. Will give you a good flavour of most of the best schools.
2. Some general decisions that need to be made:
Boarding or Day School
Single sex or Co-ed
Academically selective, super-selective, or non-selective
3. Do you have boys or girls?
If you can respond on some of these points, then the narrowing down process can begin!