@hiccupx, thanks! Using that info, I had a play with the "Modify Content-Type" extension in the Chrome Web Store.
It looks like you just need to remove the charset=UTF-8 from the "Content-Type: text/html; charset=UTF-8" header that the web server sets when serving HTML.

Web browsers seem to prioritise that header over the meta tag that specifies charset=windows-1252, resulting in them displaying pages as UTF-8 and stuffing up the curly quotes.