Have you tried it with more than one document?
Have you tried copying and pasting the entire contents of a page and using the Paste in Place command (under the Edit Menu) into the same size page in the new document?
When you have tried moving a page to a new document did you do it using the Page Panel method? The way to do this is to position the old document over the new document (which is set to the same page size) so that you can see both documents and select the pages you want to move in the Pages Panel and dragging from the Panel itself onto the pasteboard of the new document below. You will be asked where in the document you want the pages placed and when you click OK the pages from the old will become a part of the new document. This method will many times remove some funky and/or corrupt things from the original file.
Thanks for your suggestion - I did try all of this.
I think enabling auto show hidden points in the layer panel solved this for some reason.
Aha. It was a typo. You wrote "auto-show hidden points", but meant "auto-show hidden panels". I thought it was a new feature that I had missed!
Just to clarify, auto-show hidden panels means that when you press the Tab key to hide the panels, and then you mouse over them, they show up, and as you move away they hide again. It's an interface control. I'd be surprised it that setting was the source of the crashes, but what's most important is that it's working again. If you have troubles with this again down the road, just come back and let us know.