Thid list is a healthy mixture of reading levels, modern and classic texts, extended series and short novels. There's something for everyone and each is worth looking at! There are also several children's books/series, like James and the Giant Peach, Harry Potter or Anderson's Fairy Tales that may seem quite easy for children of 15+ years, but can be especially helpful for students with English as an additional language, while deepening children's understanding of English/Western culture in general.
These titles are (I believe) entirely different from any current GCSE set text lists and make for more casual reading. I recommend using both lists in conjunction with each other.
I also recommend that students Google each book before deciding to borrow or buy it, just so they can be sure they've chosen something they'll enjoy. I'm confident that any child can learn and enjoy something in each of the books on my lists. Any other books by these authors would also be worth reading!
Print the list and encourage your child or student to tick off the books they've already read, and look into any titles they think sound interesting.