The book I’m looking for is an English, children’s mystery novel set in an big rambling house, attached to a village bookshop. The main character is a boy whose family has moved there because an aged relative has recently died and left the house and the business to the boy’s father. Either the father, or the boy, is called Kit. The boy has at least one sibling. It was the first book that I’d ever read that mentioned Evensong (what? – my family is Australian and Methodist!). The house is quite close to the village green.
Anyway, the central mystery is that when the family arrives at the house/shop in the new village (I think they’ve come from London), all of the books that should be in stock in the shop – as well as all the books from the house’s library – are missing. Eventually, the boy (with other children, maybe?) discovers a hidden or secret room, with overgrown vegetation hiding the outside windows and a papered-over doorway in the front hall. Obviously, this hidden room contains all the missing books. It’s possible that A Clockwork Orange is mentioned amongst the recovered books.
I read it when I was about eleven (in the early eighties), and the copy I had was a small, second-hand, hardcover edition, with the edges of the pages stained red (I don’t remember the cover’s colour or whether it had a dust-jacket). My father was in the army, so every time we moved, mum would make me rationalize my book collection – this novel was one of the sacrifices! I would love to know a title and author, as it’s been bugging me, since I tried to describe it to a friend, over a week ago.