cassandre I found the first one a good read in that it was unusual and stimulated me to think a lot, the second I really devoured. Although someone on goodreads said the narrator seemed whiny and ungrateful... I mean my 9 year old has his moments and he hasn’t ever been on the run from the Nazis.
Thanks @SatsukiKusakabe, both sound excellent. I have a 9 year old DS too by the way!
cassandre, if you haven't read any Noel Streatfeild you are in for a treat, as long as you don't mind children's books. Ballet Shoes is the most classic.
Thanks @Tanaqui, I'm definitely a fan of children's books. Will check her out!
I'm also a fan of His Dark Materials by the way, though I found La Belle Sauvage underwhelming in comparison to the original trilogy, so haven't got round to reading The Secret Commonwealth yet. I enjoyed the BBC series a lot, though the fact I couldn't remember the details of the books very well probably helped! The leading child actors are excellent, and I can do a bit of fangirling over Lin Manuel Miranda as Lee Scoresby. 
Plus I know Oxford quite well, so it's fun to see what streets and colleges the filmmakers used. The 2007 film of The Golden Compass was shite. I'm planning to reread HDM from the beginning when I get the chance.
I heard Pullman speak in person once many years ago, and maybe it was just me, but I found him a little self-important. For example, someone asked him who his great literary influences were, and he reeled off a canonical list of Dead White Males: Shakespeare, Milton, Dickens, and so on. He seemed very keen to connect his books to Great Literature. I think his books are fantastic, so I didn't think he needed to big himself up so much. But maybe I'm being petty and unfair. Apparently when he read English at Exeter College, he got a Third. But in his generation, it was much easier to get a third than it is now, and also, there is no reason good writers are necessarily good literary critics!
I also think Pullman is ungenerous to C. S. Lewis, because if you write books as a kind of rebuttal to an author, you're still quite indebted to that author, aren't you? Anyway I'm sounding quite critical of Pullman, but on the whole, I like his books and I like him. When the boat people along the Oxford canal in Jericho were being badly treated by the local council, he stepped up to protest on their behalf.