Lots of schools conduct automatic reviews so are they all potentially limited in their appeal?
I've not actually seen any evidence that lots of admission authorities are conducting a review and then using it as a justification to limit the cope of an appeal. We deal with numerous appeals on the forum, and only occasionally are reviews mentioned.
how would I know if the review had been conducted in a fair, consistent and objective way?
It ought to be part of the authority's case (if they want to try and limit the scope of the appeal). It's just as much up to the them to prove that the review was fair, consistent and objective, as it is up to you to show otherwise. Indeed, they are meant to justify to the appeals panel what has happened.
The appeals panel, and you, have the opportunity to question and challenge the authority's case. For example:
What specialists were on the review panel? If the tests were curriculum related, were the members of the review panel specialists in the subjects being looked at, with recent teaching experience of year 7 at grammar school?
What were the guidelines under which they were operating?
Did the same panel members consider every case, and, if not, how was consistency ensured?
Was the review panel operating a quota?
Was there any restriction on the evidence that the review panel could consider?
How thorough was the review? - What was the average length of time they spent on each case?
The appeals panel then has to make a judgement about whether or not it accepts the authority's case.