Hi Blue_Alien. Welcome to the forum.
You might like to try the free open source utility
PDFMerge.
I had a a similar 'facing-pages' PDF that I wanted to extract a few pages out of. PDFMerge extracted the few pages I wanted but joy-of-joys it also unexpectedly converted the extracted PDF to standard 'single-page' format at the same time. It also retained all my bookmarks. So I was doubly happy. I don't know whether it works for all PDFs but it's worked on all the ones I've tried.