To be honest you won't get a place at any of the top 4 schools this september - The usual wait is about 1-2 years minimum to get your first kid in, them you will get sibling priority which means that you might only have to wait another year for the second kid.
Sherborne and Compass are good schools, but less popular simply because their fees are significantly higher.

Most people grab any place they can to start with and wait until a place in their preferred school comes up. it does mean having kids in different schools - but thats what we all do.

Try Doha British School as well