I recently read The Day of the Triffids and wanted to follow up with another John Wyndham, The Chrysalids. Both books are post-apocalyptic novels of the time in which they were written and represent many of the fears and thinking of the mid-twentieth century (at least as I know them from a North American perspective, which apparently aligned at least somewhat with those in Great Britain). Mid-century issues of cultural confrontation, the generation gap, and a geographical shift of power and progress from current locations are well represented in The Chrysalids. One could spend a fair bit of time discussing the use of metaphor as well - deviance and telepathy as metaphors for greater issues - and whether these are still effective means for communicating current concerns.
I would describe the tone of the book as somewhat secularly preachy (is this a thing?), but the book is overall a good post-apocalyptic story that will give the reader something to think about.