My DS also got in to Wilmington & is enjoying it.
and ask them how far away you are. I did last year and they gave it to me within 2 decimal places but do go to four if needed !!!!
With Dartford it's not down to distance as such.
See here for admissions criteria http://www.dartfordgrammar.kent.sch.uk/default.cfm?pid=6
The main part I have pasted below, but you're better off readingt he whole thing.
The main difference with Dartford is that if they can't fill the places locally then it's down to scores and not distance.
In the case of over-subscription, places are allocated in the order set out below. Within each section, places are ranked according to each applicantâ€™s combined test scores in Verbal Reasoning, Non-Verbal Reasoning and Mathematics.
1. Looked After Children: Boys under the age of 18 years for whom the Local Authority (LA) provides accommodation by agreement with their parents / carers (Section 20 of the Childrenâ€™s Act 1989) or who is subject of a care order under Part IV of the Act.
2. Zone A: Boys living in the following Electoral Wards [Brent, Bean and Darenth, Castle, Heath, Joyce Green, Joydens Wood, Littlebrook, Newtown, Princes, Stone, Sutton-at-Hone and Hawley, Town, West Hill, Wilmington.]
3. All other applicants regardless of address.
In the case of tied scores, preference is given to the applicant living nearest to the school measured in a straight line using Ordnance Survey address point data. Distances are measured from a central point within the childâ€™s house to a similarly defined point within the school as specified by Ordnance Survey. The school uses measurements provided by the Local Authority (LA) and further information on how distances are calculated is available in the Admissions Booklets provided by the LA.