The most signficant of these, from our present perspective, has to be "I Was Born in the Country", in which he describes life growing up at Whitemill along with insights into rural life in general.
Known to most people simply as H.S. the remainder of his books reflect his love of the countryside and the joys of fishing. I am told that a couple of the fishing books are now recognised as classics in the genre.
None of these books are available new. Your best bet is to try the Advanced Book Exchange - where they keep the stocklists for over 5000 booksellers, from around the world, in searchable form (give it a go - but keep your wallet locked up).
I Was Born in the Country has however recently been reprinted as "A Country Childhood" edited by Roger Guttridge (Red Post Publications) and is on sale at the mill for £12.95
His known publications are: