Thanks, email received.

Having studied the review form, my advice is that you should consider having what diplomats would call a "
full and frank exchange" with the headteacher.
A review for your son is likely to fail because of (a) the HTR (headteacher recommendation), which isn't really a recommendation, and (b) the unexplained jump in maths from a consistent EXS to a 111-120 prediction.
The HTRWith regard to (a) you could point out that there is a mismatch between the HTR and the headteacher's comments.
The headteacher refers to "
scores given by a range of subject teachers" with reservations expressed by "
one or two teachers". (Is it two, or is it one?!)
I would interpret the headteacher's reference to "
scores" as implying a lack of achievement,
and yet elsewhere the head mentions son's "academic potential" and states that he would "thrive" at a selective school.

Perhaps there isn't really an issue with academic potential?
Indeed, your latest post reports the school as suggesting instead a "
lack of motivation/engagement".
The first number in the HTR is for "
grammar school suitability", and it is clear from the definitions that this refers to suitability in terms of
academic ability (not motivation/engagement).
The second number in the HTR is for "
attitude to learning", which is surely something separate.
I would argue that, if the school truly believes there is a lack of motivation/engagement, rather than a lack of achievement, they may have allowed the second number unfairly to influence the first, which is for ability alone.
The school was not aware of the WISC results, but they were predicting 111-120 and GDS at KS2, they have highlighted the very high CAT percentiles, and they have mentioned "
academic potential" and "
thriving" at a selective school.
Why on earth wouldn't they give a 1 or a 2 for academic ability, even if they think it should be a 3 for attitude?
However, to make things even more confused, when I look at the comments for Maths, English and Science, I cannot see anything to indicate a problem with attitude. Quite the opposite! (And I think you have previously mentioned high effort grades on school reports.)
I would be inclined to put these points to the school, and ask if they would promptly write a letter of support to set the record straight.
MathsWith regard to (b), I cannot see any comment from the school to explain the jump in maths to 111-120. I doubt that the review panel will believe it, unless the school can offer some justification. Could they point to a recent test result, or refer more generally to "
greater maturity" or "
recent rapid progress"?
New evidenceThe WISC report seems very good, and I would certainly use it.
I note that the PSI would distort the result to such an extent that it has not been possible to calculate a FSIQ. The educational psychologist has had to give a GAI instead (96th percentile, which is very impressive).
I would show the report to the school, and, if they are willing to write some sort of follow-up letter for a review or appeal, perhaps they would kindly mention that they have seen this additional academic evidence, and have also noted the processing speed which is an extenuating circumstance they were previously unaware of.
P.S. There are some weaknesses in the Prior Academic Attainment (e.g. CAT quantitative 113), but I've already given you enough to think about!