TBH, in your shoes I might forget the grammar thing and look to move near a decent comprehensive in a different county (e.g. Oxted ). Trouble is, housing does tend to be expensive around such schools.
Agreed. You seem to be trying to have your cake and eat it.
Unfortunately, I suspect grammar schools are part of the REASON why non-grammar schools in their areas are often not great. Where most of the bright involved kids with committed/pushy parents are creamed off to go to grammar, that leaves far fewer of them in the non-grammars than there would be in the comprehensives of a comprehensive area.
We moved to a grammar school area largely so DC1 could go to grammar, and I know I was dreading the prospect of what to do if he didn't pass. Fortunately he did.
I totally agree too about not pushing the kid too hard when she has other emotional issues to deal with. Getting her feeling positive about things generally, and developing a sense of her own purpose, has to be priority No 1. It sounds like she needs a decent comprehensive in a nice area with not too many problem kids, where she can catch up at her own pace and have the potential to shine later if she's up to it.
I don't know personally but a friend of mine just moved to Winchester and said he wasn't particularly worried about schools because all the schools there (comprehensives) were good. Or maybe somewhere in Oxfordshire or Surrey.