Book help for an 11 year old v serious reader...

[nevernotstruggling]

If dd1 loves Harry Potter, his dark materials, Anne of green gables, Nancy Drew, Jaqueline Wilson....what else will she like?

Christ forgot how dark it was. Sorry I just remember it being my first grown up book but I was probably a couple of years older. One for the future though, it's brilliant.

If no one mentioned, how to train your dragon series, lemony snicket, spider wick chronicles...

Another series I just remembered is The Chronicles of Prydain by Lloyd Alexander. It's based on the Welsh Mabinogion, and the film The Black Cauldron is adapted from it (loosely).
Definitely one for stronger readers, but both I and my DS enjoyed them immensely around 10/11.

Try Sally Watson, historical, loosely connected.