It's not wealth it's attitude if you know what I mean. I've met some hideous hyacinth bucket types - pretty well off due to hubby having a lovely relocation package - but treat everyone else like poo on their shoe, until they learn about your family background and crawl up your backside (always a delight to see the backpedaling when they deem you 'suitable' material).
You really have to visit schools and chat at the gates to get a feel for the place.
Because if the royal connection there will be a lot of wannabes breaking down the doors.
Another thing to consider is movement of kids and teachers. It's such a shame when your child finds that their best friends leave every year - and in some cases, disappear mid term when financial disaster hits (we have seen this a few times - redundancy, recalls, illness, husband blowing all the cash on dodgy other women).
Go and look at a few schools to compare. Even state ones - st Mary Abbot's aiff high St ken comes to mind, St Georges near Berkeley sq, Hansen gurney (sp?) off edgware rd are not and have good results.
Don't be swayed by results - parents tutor like mad.