Cheerful - "Ooh, this might be where your problem lies - if everything you think is too complicated to be for children counts as YA"
Um... I haven't said anything of the sort.
Pollyanna is clearly for actual children (pre-preteen) whereas Hunger Games is clearly for at least a teenage audience, with themes such as sexual desire, intentional violence, and especially state oppression. I hope we can agree that those are not themes that 5-9 year olds would have a snowball's hope in hell of following.
Incidentally, DD read the Hunger Games trilogy last year when she was 10 and I got these faces >>>
from her friends' parents who thought they were not appropriate for her age. She enjoyed them but a lot of the story passed over her head, like I thought I would.
"If you look in Waterstones, the categories are 6-8, 9-12 and YA. Pullman isn't YA - you'd find him in 9-12, although I agree he's the upper end. 10-13ish, maybe."
My understanding of the category YA is that it means teenager/adolescent, possibly preteen depending on the themes & accessibility of the book. Your description "Upper end 10-13ish maybe" sounds like YA to me, especially since 13 is in fact teenager. So you agree with me that His Dark Materials is YA.
I see online that His Dark Materials is taught at English Lit to 11-16 year olds, which fits in with what I have been saying re it's for teenagers (YA) and not actual (rather than 'legal') children.