I have split your post out from the other thread because it really helps us to have all your information in one place. This is, essentially, your "case file".
My daughter scored an incredibly low score of 110, despite Level 5 SATS reults and NFER practice scores of 125 and 132 for 2 years running??
Can I confirm what you mean by "NFER scores for 2 years running? Were they tests that your daughter took at school?
What was the other score, and what was the order of the results?
Extenuating circumstances include her Stepfather's deployment for Afghanistan on the day of the 1st paper
Was the news first announced that day, or did he leave that day? Either way, I think that this would be taken into account by a panel as genuine mitigating circumstances. You will need to explain the impact on your daughter of his departure. You do have a great deal of ground to make up from a score of 110.
If he is still in Afghanistan, I would like to say that he has my greatest admiration, and I hope that he comes home safely.
New Head and Deputy Head in 2009, and unavoidable disruptions to the the school's dynamics and the straw that broke our backs was the 'leaking news' on the eve of the 1st paper, that the newly appointed Year 6 teacher (in Sep 09) was resigning at the end of term?
Not really relevant, because these changes would have affected all the children taking the test.
You seem to have strong mitigating circumstances, but now you must focus on obtaining all the academic evidence possible. If you have the money to do so, and you really believe that your daughter is entirely suited to a grammar school, I would suggest that you consider getting a report from an Educational Psychologist. It will unfortunately cost around Â£400.
The mid-August birthday does help - I suggest that you discuss the question of your daugther's maturity with the Head and obtain some supporting evidence from the school.