Thanks so much to everyone for your suggestions.
PB Mum: I've had mixed reports about WH, so we discounted that, also on the grounds that it is selective, although it is interesting to hear you say it is 'attainable' - I assume you mean DDs who fail the 11+ get in?
I had thought CB was selective, so good to hear that's a possibility, although I am really looking for a place that doesn't just plug away at the academics, so from what you describe, Mystery, that might not be ideal.
Kent College is also selective, and I've heard their entrance exam isn't much easier than the 11+. However, people I know whose DCs go there rave about it, so we will definitely explore it as a possibility. Apparently, sometimes you just have to agree to pay for extra coaching in the areas of your DD's weakness and they will take you. We'll see!
Thanks for other suggestions. Keen to hear from anyone with DCs there.
Re: State Schools - I'm not a snob about state education at all (DD is at a state primary), so if I could find the right fit, that would be fine by me.
However, we have no hope of getting into Bennett or St G's, as our DD isn't even baptised! And you know how it is with those schools: you have to have been attending church every Sunday for about 10 years and have a note from the priest/vicar to prove it. Also, I know a few people who have pulled their kids from St G's and moved them to indies, as they thought it was pretty awful.
Bradbourne Girls hadn't occurred to me, though, so thanks for that suggestion! Do you need to be in catchment?