Why on earth is "Heart of Darkness" on the list? I've just finished it, having been inspired to read it by the recent R4 production of Orson Welles' screenplay. It's an absolute stinker. I was expecting better, we did "The Secret Agent" at school a few decades ago and that's a hundred times better. HOD is definitely one of those books that's flattered by its screen adaptations.
H.o.d. is a guilt novel, us Brits thrive on a bit of guilt, even when it is presented in a somewhat naieve way and poorly written. Also so many people have studied it at school they can confidently throw it in their list as a way of upping the overall average intellectual content of their favourite reads. I, like doodles, am perfectly happy to list total trash as my favourites, but a lot of people feel threatened by lists, particularly the journalists compiling them, so they throw in a whole heap of what they perceive to be highbrow or controversial books to create a shield around the true reality of their personal choices.
Also the word "favourite" is ambiguous and subjective, a favourite may be a book that inspired you, made you laugh or cry or had you pinned to the edge of your seat, but it may also be a book that brings back fond memories that have little to do with script but rather more to do with where or when it was read or even the person who gave you the book.
Most importantly a personal list of favourites should never be criticised by others, it's an emotional choice and very individual opinion that reflects that person's feelings in the snapshot of time they wrote it. When a list is presented to you just smile sweetly, scan it for one book you recognise or enjoyed and focus on that.
Lists can and do change depending on our mood at the moment we were asked to form the list, the way we process our memories and interpret the contents of the books we have read will evolve, nothing s set in stone and changing your list is absolutely ok too.