According to the website they are definitely not allocating by score in catchment!
Where the number of students who have met the required standard exceed the Published Admission Number, the following criteria will be applied in the order set out below, to decide which students should be offered a place:
Eligible girls who are classed as ”Children in Care”
Eligible girls who live within the Borough of Poole
Eligible girls live outside the Borough of Poole, in rank order of the entrance test scores, with those girls obtaining the highest scores given higher priority
In the event of over-subscription in any of the criteria (a) to (c), then priority will be given to the girl whose permanent address is nearest to Parkstone Grammar School.
Might be worth asking them about this