Day of the Triffids by John Wyndham is £0.99 on
Amazon UK
As discussed before, this is the original edition.
Of interest is Daniel Ryon Sweet's Master of Arts thesis
Addressing the "Wyndham Problem": A Versioned Approach to Textual Variation in John Wyndham's Postwar Novels (
PDF) which describes the reasons for these changes (some made by Wyndham himself, with the encouragement of with his US editor Walter I. Bradbury and agent Frederik Pohl.)