Name changed as this will out me completely.
I am from Tonbridge and currently considering secondary options for DS who is just going into year 6 (he's torn between St Gregs and Tunbridge Wells Grammar for Boys) I'm also from a large family so have experienced most of the schools through younger siblings and their friends.
Skinners Academy is apparently improving since becoming an academy but still isn't a very good school, I went there when it was still Tunbridge Wells High and it was dreadful. The Knole Academy is also improving but has a long way to go, I wouldn't even consider either of them for my DS.
Trinity school in Sevenoaks is very new so i don't know anyone who has sent their DC there.
Hugh Christie is a technology specialist, they teach quite differently to the other schools in the area using something called REAL which I don't really understand but it generally has a reputation for being good for the less academic children.
St Gregs is a fantastic school, it is a specialist in Mathematics and computing and is one of the only schools in the area that really caters for all abilities (it even has a dedicated grammar stream) my eldest brother went there and youngest brother will be starting in September.
The big problem in Tonbridge/Tunbridge Wells is the slightly above average children who aren't quite academic enough for grammar have very few options, apart from St Greg's or Bennet Memorial which is CofE (or Hill View, which is all girls so no help to your DS).
Also I'd call and check what is available for DD as the good primary schools are very oversubscribed and some of the bad ones are appalling, I know quite a few people who didn't get any of their preferences and you get a lot of people every year who suddenly find God to get into schools.