I have several very close friends with children in Parish and they all rate the school differently due to the children they have.
One has a high achiever (2 years above expectations) and a second one bang in the middle, no problems at all, all honky-dory.
One with a child with no social or academical problems, child no. 2 just started Reception. Usual niggles with communication (the school is notoriously bad with information about inset days, dress up days and relies heavily on paper for all kind of permission/parent evenings etc).
One with a DD with suspected dyslexia, just started Y6 and the mum (herself has dyslexia) struggled for years to get the school to test/help/acknowledge a problem. It seems the Y5 teacher said now something, let's see how the Y6 teacher acts. Also the girl suffered from bullying which the school knew off but didn't bother telling the parents despite asking and when the truth came out they hardly helped to solve the issue.
Friend no. 4, one high achiever, doing ok. Child 2 is struggling in Y2 (academically and socially), they are looking to move anyway and said they would change schools if they could immediately but didn't want to uproot them twice as they plan to move out of the area completely.
So, it very much depends on your child in my opinion. The 3-form-entry seems to work ok.
Depending where you live, could other schools be an alternative? Scotts Park?