You are the second person mentioning a child not being able to get into Gravesend grammer school while living in Hartley. Going off the Gravesend website, it states that Hartley is in catchment. Strange!!!
Taken from the Gravesend Grammar School website:
A Parents’ Guide to Year 7 Admissions -
How Places are allocated at Gravesend Grammar School
Each year, Gravesend Grammar School has more applications than there are places available. We rank applicants using the following criteria in the order they appear. Places are awarded to highest ranked students.
Children who are in Local Authority Care
Children whose mental or physical impairment means they have a demonstrable and significant need to attend a particular school.
Children who have a brother (or sister in the 6th Form) who will be attending the school when the applicant joins.
Children who have a parent who is a member of staff
Children who live within the Borough of Gravesham.
Children who live within the civil parishes of Ash-cum-Ridley, Bean, Fawkham, Hartley, Longfield and New Barn, Southfleet, Swanscombe and Greenhithe and Stansted.
Children who live within the civil parishes of Stone, Darenth, Horton Kirby and South Darenth, Cliffe and Cliffe Woods