Welcome!

If in doubt, our usual advice is to take your case to an appeal panel and get their opinion. It's a free service!
Keep your options open.
https://www.elevenplusexams.co.uk/appeals/general#a49But you must be realistic. Most appeals are not going to succeed.
Will your headteacher support going to appeal? Ideally you need a letter to say that daughter is on target for GDS/111-120.
Where there is a jump from EXS in Y5 to a prediction of 111-120, the school needs to justify and explain its prediction (e.g. greater maturity, recent rapid progress, the evidence of mock SATs papers).
You do not have to provide the letter now - it could be submitted nearer the appeal.
If you want to keep all your options open, you need write very little on the appeal form at this point in time.
Have you read our Bucks sticky?
viewtopic.php?f=12&t=57343See D11.
We suggest some wording you could use to argue that the review was not fair, consistent and objective.
And for your academic case and reasons for wanting a place you could basically say little more than "full details of case to follow".