Hello Mrs Crane (I always preferred Niles!),
I grew up in Durham and attended DJCS, 20+ years ago. I don't know people with children in the area now but if I might offer you some wildly out of date thoughts, they are these.
Firstly, Durham's a lovely place to grow up. It is small enough to allow teenagers a lot of freedom, yet only a 20 minute train ride from Newcastle. So small though, that everyone leaves to form a life elsewhere, unlike larger cities where people may stay or return.
Like many children at DJCS one of my parents was a university lecturer. Other friends' parents were doctors and teachers. There is a culture of natural academic aptitude and expectation amongst a significant proportion of pupils. In my day ex-grammar-school teachers (probably long gone), operated informal elites with extra-curricular chess and bridge clubs, drama favourites and debating teams that were the only state entrants in their competitions. There were wonderful opportunities with drama, skiing trips, optional classes in Spanish, Russian and a sixth form Japanese exchange. Sport was not priority though and the PE teachers focused on the naturally able pupils in a desperate effort to cobble teams together.
It was almost 2 or 3 schools in one though, with the academic, middle class children forming a critical mass - so no need to dumb down to fit in, as people can find in comps where academic achievement is not the norm. Then there were the 'lower band' children (for first three years we were grouped into upper and lower) and the in between ones. My concern would be about your dd's dyslexia. You must quiz them about how this will be accommodated. Really pleased to read mummytime's comment. In my day I'd have been concerned that she'd have been thrown in with unmotivated, less bright children and dragged down.
Parents I knew of children with learning difficulties chose St Leonard's because of its more inclusive, supportive approach, recognising they'd have been hugely disadvantaged by DJCS's streaming.
Amazed to read Durham School is co-ed! As a boys' school they had a very strong focus on sport. Back then DHSFG didn't seem so academic. Newcastle Central High was the nearest academically strong girls' independent.