"School capacity is 580 and anticipated number starting in sept is 553 so they have a
Spare 27 places across all year groups = 4.66% available"
Irrelevant. What matters is whether her year group is full. They won't be able to cite overcrowding in the halls, etc., but they will say, rightly, that the year group is full.
"118 spaces allowed in year 8 - without appeal? How have the extra 2 pupils above PAN been managed?"
This is worth exploring. Just be aware that they could answer that they've really struggled, that there was insufficient IT equipment, that science lessons had to be adapted, etc., which might work against you rather than for you.
"New building so from Nov 24 capacity will be 700 - so 140 per year group.
Penalised for applying this year when capacity would allow her in next school year?"
Irrelevant for this appeal. They may well also say that their teaching arrangements for this year group is x classes of y size and that from next year year 7 will have z classes of y size, but the class size won't change.
"Only pupil in her school to not get a place at her first preference school."
That's the rub. Sometimes people don't get places. It won't help your case.
"MAT pupil
Prefect
Criw Cymraeg rep through whole of school.
Plays netball for team linked to the High school
Featured alongside 2 best friends in a photo taken on a transition day that was used as promotional material for open evening - massively got her hopes up!"
All irrelevant, I'm afraid. Appeals panels are prohibited from considering the 'value' of a child to the school. They can only consider the value of the school to the child.
Compare both schools and look for all the positives of your preferred school. Base your appeal on that.