1) go through all the pages, and group all the objects to ensure they don't move around. (make a reactangle the size of the page and label it for later removal.
2) change the page size to half of the current and portrait instead of landscape.
3) Make sure your rulers are spread not page
4) confirm that your group is aligned to the spread bounds.
5) ungroup and remove bounding frame
Thanks. I can figure out how to change the page size and orientation via script. What I'd also need the script to do then is add a new page and make sure that page is correctly appended to the first page to create a spread, rather than one page with a second page underneath in the Pages panel. I've looked through the CS3 scripting manual (which is the only one I could see - I'm using CS4), and it doesn't cover this at all as far as I can see.
Anyone know the intricacies of document manipulation via script please?
If I can do that then I can combine with Harbs' suggestion, I think, to create a script that splits the pages.
After adding the pages, make sure the doc documentPreferences.allowPageShuffle and spread.allowPageShuffle are both true.
Again, thanks for the reply.
"spread" isn't showing as a valid object and I can't find it in the scripting guide either.
However, I think I've got some other, probably embarassingly simple problem. When I check in the Pages panel, Allow document pages to Shuffle and Allow Selected spread to shuffle are both checked. But... I can;t even manually seem to drag page 2 to be beside page 1 now, so they won't attach to create a spread even manuallu never mind in script.
I'm obviously doing something really simple wrong here.