For years, the grammar school offered priority places to successful Kent Test pupils who live in Dartford borough but the catchment area did not include Greenhithe, Swanscombe or Longfield.
From September 2015 that will change, when the school will be expanding to accept 180 Kent Test children, compared to 150 in recent years.
But another change to the admissions procedure could spell difficulties for some would-be pupils.
Previously, there was no limit to how many local children could take those 150 places, but now a maximum of 90 spaces could be set aside for Dartford’s 11-year-olds.
If over-subscribed, places would be allocated first to children supported by the local authority.
Then up to a maximum of 90 places would be reserved for boys who live within the Dartford electoral wards.
The remaining places will be offered to applicants outside the borough, based on their test scores.
So pupils from Dartford might have to compete with each other to get a place at the Dartford school.
Some could miss out, while boys in London or elsewhere in Kent are given a place.
Cllr David Mote said the good news about expanding the catchment area to Greenhithe, Swanscombe and Longfield came after he and fellow councillor Keith Kelly had raised their concerns with the school.
They both represent Greenhithe on Dartford council.
Cllr Mote said: “Cllr Kelly and myself pursued the issue of successful Greenhithe children, having passed their 11-plus, not being recognised as Dartford residents, since we were elected as borough councillors.
“This is quite a win for both the children in our ward and for us personally.”
Cllr Mote added: “We understand the change of the admission arrangements was not as easy as it sounds and really appreciate the school working with us on this enrolment anomaly.”
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